# EDGAR Filing Document

**Accession Number:** 0001681087
**File Stem:** 0001193125-25-159404
**Filing Date:** 2025-7
**Character Count:** 160157
**Document Hash:** edf9ffbdd65a054c820e30e096e44759
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-25-159404.hdr.sgml**: 20250715

**ACCESSION NUMBER**: 0001193125-25-159404

**CONFORMED SUBMISSION TYPE**: 424B3

**PUBLIC DOCUMENT COUNT**: 2

**FILED AS OF DATE**: 20250715

**DATE AS OF CHANGE**: 20250715

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Tectonic Therapeutic, Inc.
- **CENTRAL INDEX KEY:** 0001681087
- **STANDARD INDUSTRIAL CLASSIFICATION:** BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 810710585
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 424B3
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 333-288539
- **FILM NUMBER:** 251125385

**BUSINESS ADDRESS:**
- **STREET 1:** 490 ARSENAL WAY
- **STREET 2:** SUITE 210
- **CITY:** WATERTOWN
- **STATE:** MA
- **ZIP:** 02472
- **BUSINESS PHONE:** (339) 666-3320

**MAIL ADDRESS:**
- **STREET 1:** 490 ARSENAL WAY
- **STREET 2:** SUITE 210
- **CITY:** WATERTOWN
- **STATE:** MA
- **ZIP:** 02472

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** AVROBIO, Inc.
- **DATE OF NAME CHANGE:** 20180131

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** AvroBio, Inc.
- **DATE OF NAME CHANGE:** 20160729

##### [**Table of Contents**](#toc)
**As Filed Pursuant to Rule 424(b)(3) <br>Registration No. 333-288539** 

**PROSPECTUS SUPPLEMENT** 

**(To Prospectus dated July 15, 2025)** 

**Up to $100,000,000**![LOGO](g49849g04g04.jpg)

**Common Stock** 

We have entered into a sales agreement with TD Securities (USA) LLC ("TD Cowen"), dated as of July 7, 2025 (the "sales agreement"), relating to the sale of shares of our common stock, par value $0.0001 per share (the "common stock"), offered by this prospectus supplement. In accordance with the terms of the sales agreement, we may offer and sell shares of our common stock under this prospectus supplement having an aggregate gross sales price of up to $100,000,000 from time to time through TD Cowen acting as our sales agent or principal.

Our common stock is listed on the Nasdaq Global Market ("Nasdaq") under the symbol "TECX." On July 14, 2025, the last reported sale price of our common stock on Nasdaq was $23.12 per share.

Sales of our common stock, if any, under this prospectus supplement will be made in negotiated transactions, including block trades or block sales, or at market prices by any method that is deemed to be an "at the market offering" as defined in Rule 415(a)(4) promulgated under the Securities Act of 1933, as amended (the "Securities Act"), including without limitation sales made through Nasdaq or on any other trading market for our common stock, or by any other method permitted by law. TD Cowen is not required to sell any specific amount of securities, but will act as our sales agent using commercially reasonable efforts consistent with its normal trading and sales practices, on mutually agreed terms between TD Cowen and us. There is no arrangement for funds to be received in any escrow, trust or similar arrangement.

The compensation to TD Cowen for sales of common stock pursuant to the sales agreement will be an amount up to 3.0% of the gross proceeds of any shares of common stock sold under the sales agreement. In connection with the sale of the common stock on our behalf, TD Cowen will be deemed to be an "underwriter" within the meaning of the Securities Act and the compensation of TD Cowen will be deemed to be underwriting commissions or discounts. We have also agreed to provide indemnification and contribution to TD Cowen with respect to certain liabilities, including liabilities under the Securities Act or the Securities Exchange Act of 1934, as amended (the "Exchange Act").

We are a "smaller reporting company" under the federal securities laws and, as such, we have elected to comply with certain reduced public company reporting requirements for this prospectus supplement and for future filings. See ''Prospectus Summary—Implications of Being a Smaller Reporting Company" on page S-2 of this prospectus supplement.

**Investing in our common stock involves a high degree of risk. Before making an investment decision, you should carefully review the risks and uncertainties described under the heading "[Risk Factors](#supprom49849_3)" beginning on page S-4 of this prospectus supplement and under similar headings in the documents that we have filed or that are filed after the date hereof and are incorporated by reference into this prospectus supplement.** 

**Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement is truthful or complete. Any representation to the contrary is a criminal offense.** 

**TD Cowen** 

**The date of this prospectus supplement is July 15, 2025** 

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##### [**Table of Contents**](#toc)
**TABLE OF CONTENTS** 

**PROSPECTUS SUPPLEMENT** 

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|:---|:---|
|  | **Page** |
|  [ABOUT THIS PROSPECTUS SUPPLEMENT](#supprom49849_1) | S-ii |
|  [PROSPECTUS SUPPLEMENT SUMMARY](#supprom49849_2) | S-1 |
|  [RISK FACTORS](#supprom49849_3) | S-4 |
|  [SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS](#supprom49849_4) | S-6 |
|  [USE OF PROCEEDS](#supprom49849_5) | S-7 |
|  [DILUTION](#supprom49849_6) | S-8 |
|  [PLAN OF DISTRIBUTION](#supprom49849_7) | S-10 |
|  [LEGAL MATTERS](#supprom49849_8) | S-11 |
|  [EXPERTS](#supprom49849_9) | S-11 |
|  [WHERE YOU CAN FIND MORE INFORMATION](#supprom49849_10) | S-11 |
|  [INCORPORATION OF CERTAIN INFORMATION BY REFERENCE](#supprom49849_11) | S-12 |

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**PROSPECTUS** 

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|:---|:---|
|  | **Page** |
|  [ABOUT THIS PROSPECTUS](#rom49849_1) | ii |
|  [PROSPECTUS SUMMARY](#rom49849_2) | 1 |
|  [RISK FACTORS](#rom49849_3) | 4 |
|  [SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS](#rom49849_4) | 5 |
|  [USE OF PROCEEDS](#rom49849_5) | 6 |
|  [DESCRIPTION OF CAPITAL STOCK](#rom49849_6) | 7 |
|  [DESCRIPTION OF DEBT SECURITIES](#rom49849_7) | 11 |
|  [DESCRIPTION OF WARRANTS](#rom49849_8) | 18 |
|  [LEGAL OWNERSHIP OF SECURITIES](#rom49849_9) | 21 |
|  [PLAN OF DISTRIBUTION](#rom49849_10) | 24 |
|  [LEGAL MATTERS](#rom49849_11) | 26 |
|  [EXPERTS](#rom49849_12) | 26 |
|  [WHERE YOU CAN FIND MORE INFORMATION](#rom49849_13) | 26 |
|  [INCORPORATION OF CERTAIN INFORMATION BY REFERENCE](#rom49849_14) | 27 |

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S-i

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**ABOUT THIS PROSPECTUS SUPPLEMENT** 

This prospectus supplement and the accompanying base prospectus are part of a registration statement that we have filed with the U.S. Securities and Exchange Commission (the "SEC"), utilizing a "shelf" registration process. Under the shelf registration statement, we may offer shares of our common stock, preferred stock, debt securities and warrants, including common stock or preferred stock upon conversion of debt securities, common stock upon conversion of preferred stock, or common stock, preferred stock or debt securities upon the exercise of warrants. Under this prospectus supplement, we may offer shares of our common stock having an aggregate gross proceeds of up to $100,000,000 from time to time at prices and on terms to be determined by market conditions at the time of offering.

This prospectus supplement and the accompanying base prospectus relate to the offering of our common stock. Before buying any of the common stock that we are offering, we urge you to carefully read this prospectus supplement and the accompanying base prospectus, together with the information incorporated by reference herein and therein as described under the headings "Where You Can Find More Information" and "Incorporation of Certain Information by Reference" in this prospectus supplement and the accompanying base prospectus. These documents contain important information that you should consider when making your investment decision.

This prospectus supplement describes the terms of this offering of common stock and also adds to and updates information contained in the accompanying base prospectus and the documents incorporated by reference into this prospectus supplement and the accompanying base prospectus. If there is a conflict between the information contained in this prospectus supplement and the information contained in the accompanying base prospectus, you should rely on the information in this prospectus supplement. To the extent there is a conflict between the information contained in this prospectus supplement, on the one hand, and the information contained in any document incorporated by reference into this prospectus supplement that was filed with the SEC before the date of this prospectus supplement, on the other hand, you should rely on the information in this prospectus supplement. If any statement in one of these documents is inconsistent with a statement in another document having a later date (for example, a document incorporated by reference into this prospectus supplement) the statement in the document having the later date modifies or supersedes the earlier statement.

We have not, and TD Cowen has not, authorized anyone to provide you with information in addition to or different from that contained in or incorporated by reference into this prospectus supplement. We are not, and TD Cowen is not, making an offer to sell or soliciting an offer to buy our securities in any jurisdiction where an offer or solicitation is not authorized or in which the person making that offer or solicitation is not qualified to do so or to anyone to whom it is unlawful to make an offer or solicitation. You should assume that the information appearing in this prospectus supplement, the documents incorporated by reference into this prospectus supplement, and in any free writing prospectus that we have authorized for use in connection with this offering, is accurate only as of the date of those respective documents. Our business, financial condition, results of operations and prospects may have changed since those dates. You should read this prospectus supplement, the accompanying base prospectus, the documents incorporated by reference herein and therein, and any free writing prospectus that we have authorized for use in connection with this offering, in their entirety before making an investment decision.

Unless the context requires otherwise, references in this prospectus supplement to the "Company," "Tectonic," "we," "us" and "our" refer to Tectonic Therapeutic, Inc.

S-ii

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**MARKET AND INDUSTRY DATA** 

Certain information contained in, or incorporated by reference into, this prospectus supplement relates to or is based on studies, publications, surveys and other data obtained from third-party sources and our own internal estimates and research. While we believe these third-party sources to be reliable as of the date of this prospectus supplement, we have not independently verified the market and industry data contained in this prospectus supplement or the underlying assumptions relied on therein. Finally, while we believe our own internal research is reliable, such research has not been verified by any independent source. Notwithstanding the foregoing, we are liable for the information provided in this prospectus supplement.

S-iii

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**PROSPECTUS SUPPLEMENT SUMMARY** 

*This summary highlights certain information about us, this offering and selected information contained elsewhere in or incorporated by reference into this prospectus supplement. This summary is not complete and does not contain all of the information that you should consider before deciding whether to invest in our common stock. For a more complete understanding of our Company and this offering, we encourage you to read and consider carefully the more detailed information in this prospectus supplement, the accompanying base prospectus, including the information incorporated by reference herein and therein, and the information included in any free writing prospectus that we have authorized for use in connection with this offering, including the information under the heading "[Risk Factors](#supprom49849_3)" in this prospectus supplement beginning on page S-4 and in the documents incorporated by reference into this prospectus supplement.* 

**Company Overview** 

We are a clinical-stage biotechnology company focused on the discovery and development of therapeutic proteins and antibodies that modulate the activity of G-protein coupled receptors ("GPCRs"). The discovery of biologics that can modulate GPCRs has historically been quite challenging. We have developed a proprietary technology platform called GEODe<sup>™</sup>, with the aim of addressing these challenges to enable the discovery and development of GPCR-targeted biologic medicines that can modify the course of disease. We focus on areas of significant unmet medical need, often where therapeutic options are poor or nonexistent, as these are areas where new medicines have the potential to improve patient quality of life or extend duration of life.

Our lead asset, TX45, is an Fc-relaxin fusion molecule that activates the RXFP1 receptor, the GPCR target of the hormone, relaxin. In September 2024, we announced favorable results from a Phase 1a trial evaluating safety, tolerability and pharmacokinetic ("PK") and pharmacodynamic ("PD") properties for TX45. In this trial, TX45 was well-tolerated with no drug-related severe adverse events, no observed immunogenicity and demonstrated a favorable PK/PD relationship. Renal plasma flow was measured in each patient at several time points as a PD marker. This data was used to develop an exposure-response model which enabled the selection of doses for the APEX Phase 2 trial.

We are currently evaluating TX45 in a Phase 1b Part B hemodynamic clinical trial and in the APEX Phase 2 clinical trial. Part A of the TX45 Phase 1b hemodynamic clinical trial was a single intravenous dose, open-label clinical trial that evaluated the safety, tolerability, and acute hemodynamic effects of TX45 in subjects with Group 2 Pulmonary Hypertension in Heart Failure with preserved Ejection Fraction ("PH-HFpEF"). Part B which is still enrolling has a similar design but is being conducted in subjects with Group 2 Pulmonary Hypertension in Heart Failure with reduced Ejection Fraction ("PH-HFrEF"). APEX is a 24-week, placebo-controlled trial designed to evaluate the safety and efficacy of TX45 administered subcutaneously ("SC") in subjects with PH-HFpEF. In May 2025, we announced the complete results from Part A of the Phase 1b clinical trial of TX45 in subjects with PH-HFpEF. The complete data from Part A confirmed the tolerability and hemodynamic effects of TX45 in patients with PH-HFpEF previously reported in the interim data. Based on the complete dataset, TX45 was well-tolerated in subjects with PH-HFpEF with no serious or severe adverse events. In the overall study population, TX45 achieved a 19.0% reduction in pulmonary capillary wedge pressure ("PCWP"), an endpoint known to correlate with exercise capacity, morbidity and mortality in patients with heart failure. In the subpopulation with combined pre- and post-capillary pulmonary hypertension who have an elevated Pulmonary Vascular Resistance ("PVR") and more severe disease, TX45 demonstrated >30% reduction in PVR, which along with PCWP is correlated to exercise capacity and mortality in this patient population. The Phase 1b Part A clinical trial enrolled a patient population and evaluated hemodynamic endpoints which are similar to the ongoing APEX Phase 2 clinical trial. We dosed our first patient in the APEX Phase 2 clinical trial in October 2024. Subjects will be randomized to 300 mg SC once monthly of TX45, 300 mg SC once every other week of TX45, or placebo. We expect topline trial results from the APEX clinical trial in 2026. Part B of the Phase 1b trial,

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which is assessing the acute hemodynamic effects of TX45 in subjects with Group 2 PH-HFrEF enrolled its first patient in the first half of 2025 with data expected to be announced in the second half of 2025.

We are also evaluating TX002100 ("TX2100") as our second development candidate for the treatment of Hereditary Hemorrhagic Telangiectasia ("HHT"), the second most common genetic bleeding disorder with no current approved therapy. TX2100 is a VHH-Fc fusion antagonist antibody that binds to an undisclosed GPCR target which plays a key role in pathogenic angiogenesis. A rodent surrogate of TX2100 demonstrated reduced arteriovenous malformation development and bleeding in an animal model of HHT. A 4-week non-human primate dose-range study with a functionally equivalent precursor to TX2100 showed no treatment-related toxicity observed at doses up to 100 mg/kg. A formulation supporting TX2100 SC dosing has been identified. Both Investigational New Drug ("IND")-enabling non-human primate good laboratory practices toxicology studies and technical development activities to generate good manufacturing practice drug supply and drug product for TX2100 started in the second quarter of 2025. We expect to initiate a Phase 1 clinical trial for TX2100 in the fourth quarter of 2025 or the first quarter of 2026, subject to the results of IND-enabling studies.

**Corporate Information** 

We were incorporated under the laws of the State of Delaware in November 2015. Legacy Tectonic (as defined below) was incorporated under the laws of the State of Delaware in June 2019. On January 30, 2024, we entered into the Agreement and Plan of Merger and Reorganization (the "Merger Agreement") with Tectonic Operating Company, Inc. (previously Tectonic Therapeutic, Inc., referred to as "Legacy Tectonic") and Alpine Merger Subsidiary, Inc. ("Merger Sub"). Pursuant to the Merger Agreement, on June 20, 2024, Merger Sub merged with and into Legacy Tectonic, with Legacy Tectonic surviving as our wholly owned subsidiary (the "Merger"). In connection with the completion of the Merger, we changed our name from "AVROBIO, Inc." to "Tectonic Therapeutic, Inc." Our principal executive office is located at 490 Arsenal Way, Suite 210, Watertown, Massachusetts 02472, and our telephone number is (339) 666-3320. Our website address is www.tectonictx.com. We do not incorporate the information on or accessible through our website into this prospectus supplement, and you should not consider any information on, or that can be accessed through, our website as part of this prospectus supplement. Our common stock is listed on Nasdaq under the symbol "TECX."

This prospectus supplement contains references to our trademarks and to trademarks belonging to other entities. Solely for convenience, trademarks and trade names referred to in this prospectus supplement, including logos, artwork and other visual displays, may appear without the <sup>®</sup> or TM symbols, but such references are not intended to indicate, in any way, that their respective owners will not assert, to the fullest extent under applicable law, their rights thereto. We do not intend our use or display of other companies' trade names or trademarks to imply a relationship with, or endorsement or sponsorship of us by, any other companies.

**Implications of Being a Smaller Reporting Company** 

Additionally, we are currently a "smaller reporting company" as defined in Item 10(f)(1) of Regulation S-K. Smaller reporting companies may take advantage of certain reduced disclosure obligations, including, among other things, providing only two years of audited financial statements. We may continue to be a smaller reporting company if either (i) the market value of our stock held by non-affiliates is less than $250.0 million or (ii) our annual revenue was less than $100.0 million during the most recently completed fiscal year and the market value of our stock held by non-affiliates is less than $700.0 million. Specifically, as a smaller reporting company we may choose to present only the two most recent fiscal years of audited financial statements in our Annual Report on Form 10-K and have reduced disclosure obligations regarding executive compensation.

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**THE OFFERING** 

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|:---|:---|
| **Common stock offered by us**  | Shares of our common stock having an aggregate offering price of up to $100,000,000. |

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|:---|:---|
| **Common stock to be outstanding after this offering**  | Up to 23,357,265 shares (as more fully described in the notes following this table), assuming sales of $100.0 million of shares of our common stock in this offering at an assumed offering price of $21.34 per share, which was the last reported sale price of our common stock on Nasdaq on July 3, 2025. The actual number of shares issued will vary depending on the prices at which shares of our common stock are sold in this offering. |

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| **Plan of Distribution**  | "At the market offering" that may be made from time to time through our sales agent, TD Cowen. See "Plan of Distribution." |

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|:---|:---|
| **Use of Proceeds**  | We currently intend to use the net proceeds from this offering for continued clinical development of pipeline products, working capital and other general corporate purposes. See "Use of Proceeds." |

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|:---|:---|
| **Risk Factors**  | Investing in our common stock involves significant risks. See "Risk Factors" beginning on page S-4 of this prospectus supplement, and under similar headings in documents incorporated by reference into this prospectus supplement and in the accompanying base prospectus. |

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|:---|:---|
| **Nasdaq Global Market symbol**  | "TECX" |

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The number of shares to be outstanding after this offering is based on 18,671,229 shares of our common stock outstanding as of March 31, 2025, and excludes:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• 1,791,232 shares of common stock issuable upon the exercise of outstanding stock options at a weighted average
exercise price of $19.32 under our 2019 and 2024 Equity Incentive Plan as of March 31, 2025;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• 31,891 shares of common stock issuable upon the exercise of outstanding options at a weighted average exercise
price of $40.80 under the AVROBIO, Inc. 2018 Equity Incentive Plan as of March 31, 2025;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• 181,987 shares of common stock issuable upon the settlement of outstanding restricted stock units as of
March 31, 2025;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• 1,227,159 shares of common stock reserved for future issuance under our 2024 Equity Incentive Plan as of
March 31, 2025; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• 295,906 shares of common stock reserved for future issuance under our 2024 Employee Stock Purchase Plan as of
March 31, 2025.

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**RISK FACTORS** 

*Investing in our common stock involves a high degree of risk. You should carefully review the risks and uncertainties described below and under the section titled "Risk Factors" in our most recent Annual Report on Form 10-K, and any subsequent Quarterly Reports on Form 10-Q or Current Reports on Form 8-K we file after the date of this prospectus supplement, and all other information contained in or incorporated by reference into this prospectus supplement, before deciding whether to purchase any common stock in this offering. Each of the risk factors could adversely affect our business, operating results and financial condition, as well as adversely affect the value of an investment in our common stock, and the occurrence of any of these risks might cause you to lose all or part of your investment. Additional risks not presently known to us or that we currently believe are immaterial may also significantly impair our business operations. Please also carefully read the section below titled "Special Note Regarding Forward-Looking Statements."* 

**Additional Risks Related to This Offering** 

***Management will have broad discretion as to the use of the net proceeds from the shares of common stock we are selling in this offering, and we may not use these proceeds effectively.***

Our management will have broad discretion in the application of the net proceeds from the shares of common stock we are selling in this offering and could spend these proceeds in ways that do not improve our results of operations or enhance the value of our common stock. Our failure to apply these funds effectively could have a material adverse effect on our business, delay the development of our product candidates, and cause the price of our common stock to decline.

***If you purchase shares of our common stock in this offering, you may experience immediate and substantial dilution in the net tangible book value of your shares. In addition, we may issue additional equity or convertible debt securities in the future, which may result in additional dilution to you.***

The offering price per share of our common stock in this offering may exceed the net tangible book value per share of our common stock outstanding prior to this offering. The prices at which we sell shares in this offering will vary and these variations may be significant. Purchasers of the shares we sell, as well as our existing stockholders, will experience significant dilution if we sell shares at prices significantly below the price at which they invested. In addition, to the extent we need to raise additional capital in the future and we issue additional shares of common stock or securities convertible or exchangeable for our common stock, our then existing stockholders may experience dilution and the new securities may have rights senior to those of our common stock offered in this offering. See the section titled "Dilution" for an illustration of the dilution you may incur if you participate in this offering.

In addition to this offering, subject to market conditions and other factors, we may pursue additional equity financings in the future, including future public offerings or future private placements of equity securities or securities convertible into or exchangeable for equity securities. Further, the exercise of outstanding stock options or the exercise of stock options issued in the future could result in further dilution to investors and any additional shares issued in connection with acquisitions, should we choose to pursue any, will result in dilution to investors.

***A sale of a substantial number of shares of our common stock may cause the price of our common stock to decline.***

Sales of a substantial number of shares of our common stock in the public market could occur at any time. If our stockholders sell, or the market perceives that our stockholders intend to sell, substantial amounts of our common stock in the public market, the market price of our common stock could decline significantly. In addition, the market price of our common stock could fall as a result of resales of any of our shares of common stock due to an increased number of shares available for sale in the market.

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We cannot predict what effect, if any, sales of our shares in the public market or the availability of shares for sale will have on the market price of our common stock. However, future sales of substantial amounts of our common stock in the public market, including shares issued upon exercise of outstanding options or warrants, or

the perception that such sales may occur, could adversely affect the market price of our common stock.

***The actual number of shares we will issue, and the aggregate proceeds resulting therefrom, under the sales agreement, at any one time or in total, is uncertain.***

Subject to certain limitations in the sales agreement and compliance with applicable law, we have the discretion to deliver a placement notice to TD Cowen to sell shares of our common stock at any time throughout the term of the sales agreement. The number of shares that are sold by TD Cowen after delivering a placement notice will fluctuate based on a number of factors, including the market price of our common stock during the sales period and limits we set with TD Cowen in any placement notice to sell shares, and the demand for our common stock during the sales period. Because the price per share of each share sold will fluctuate based on the market price of our common stock during the sales period, it is not possible at this stage to predict the number of shares that will be ultimately issued or the aggregate proceeds to be raised in connection with those sales.

***The common stock offered hereby will be sold in "at the market offerings," and investors who purchase shares at different times will likely pay different prices.***

Investors who purchase shares in this offering at different times will likely pay different prices, and therefore may experience different levels of dilution and different outcomes in their investment results. We will have discretion, subject to market demand, to vary the timing and price of sales and the number of shares sold. In addition, subject to any restrictions in any applicable placement notice delivered to TD Cowen, there is no minimum or maximum sales price for shares to be sold in this offering. Investors may experience a decline in the value of their shares they purchase in this offering as a result of sales made at prices lower than the prices they paid.

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**SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS** 

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• our strategies, prospects, plans, expectations or objectives of management for our future operations;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• our progress, scope or timing of the development of our product candidates;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• our expectations surrounding the potential safety, efficacy, and regulatory and clinical progress of TX45, TX2100
and any other product candidates, and our anticipated milestones and timing therefor;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the benefits that may be derived from any of our future products, if approved, or the commercial or market
opportunity with respect to any of our future products, if approved;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• our ability to protect our intellectual property rights;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• our anticipated operations, financial position, ability to raise capital to fund our operations, revenues, costs
or expenses;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the effects of macroeconomic and geopolitical conditions and unforeseeable events;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• our expectations regarding the use of proceeds from offerings of our securities under this prospectus supplement;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• other factors set forth in documents filed, or to be filed, with the SEC; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the statements regarding our future economic conditions or performance, statements of belief and any statement of
assumptions underlying any of the foregoing.

In some cases, you can identify forward-looking statements by terms such as "anticipates," "believes," "could," "estimates," "expects," "goal," "intends," "may," "plans," "potential," "predicts," "projects," "should," "will," "would," the negative of these words and words or similar expressions intended to identify forward-looking statements. These statements reflect our views as of the date on which they were made with respect to future events and are based on assumptions and subject to risks and uncertainties. The underlying information and expectations are likely to change over time. In addition, statements that "we believe" and similar statements reflect our beliefs and opinions on the relevant subject. These statements are based upon information available to us as of the date the statement is made, and while we believe such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that we have conducted an exhaustive inquiry into, or review of, all potentially available relevant information. These statements are inherently uncertain and you are cautioned not to unduly rely upon these statements.

Given these uncertainties, you should not place undue reliance on these forward-looking statements as actual events or results may differ materially from those projected in the forward-looking statements due to various factors, including, but not limited to, those set forth under the heading "Risk Factors" in this prospectus supplement and the documents incorporated by reference herein or any free writing prospectus that we authorize for use in connection with this offering. These forward-looking statements represent our estimates and assumptions only as of the date of the document containing the applicable statement. Our actual future results may be materially different from what we expect. We qualify all of the forward-looking statements contained in this prospectus supplement and in the documents incorporated by reference herein by these cautionary statements. Unless required by law, we undertake no obligation to update or revise any forward-looking statements to reflect new information or future events or developments. Thus, you should not assume that our silence over time means that actual events are bearing out as expressed or implied in such forward-looking statements. Before deciding to purchase our common stock in this offering, you should carefully consider the risk factors discussed herein or incorporated by reference, in addition to the other information set forth in this prospectus supplement, any free writing prospectus we authorize for use in connection with this offering and in the documents incorporated by reference.

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**USE OF PROCEEDS** 

We may issue and sell shares of our common stock under this prospectus supplement having aggregate gross sales proceeds of up to $100.0 million from time to time. Because we are not required to sell any shares of our common stock under the sales agreement, and any shares that may be sold pursuant to the sales agreement will be sold in "at the market offerings" at fluctuating prices, the actual total public offering amount, commissions and proceeds to us, if any, are not determinable at this time. There can be no assurance that we will sell any shares of our common stock under or fully utilize the sales agreement as a source of financing.

We currently intend to use the net proceeds from this offering for continued clinical development of pipeline products, working capital and other general corporate purposes. We may also use the net proceeds to in-license, acquire or invest in complementary businesses, technologies, products or assets. However, we have no current commitments or obligations to do so. As of the date of this prospectus supplement, we cannot specify with certainty all of the particular uses of the net proceeds, if any, from this offering. Accordingly, we will retain broad discretion over the use of any such proceeds. Pending the use of the net proceeds from this offering, we intend to invest the net proceeds in investment-grade, interest-bearing instruments.

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**DILUTION** 

Our net tangible book value as of March 31, 2025 was approximately $301.0 million, or $16.12 per share of common stock. Net tangible book value per share is determined by dividing our total tangible assets, less total liabilities, by the number of shares of our common stock outstanding as of March 31, 2025. Dilution with respect to net tangible book value per share represents the difference between the amount per share paid by purchasers of shares of common stock in this offering and the as adjusted net tangible book value per share of our common stock immediately after giving effect to this offering.

After giving effect to the sale of 4,686,036 shares of our common stock in this offering at an assumed public offering price of $21.34 per share, the last reported sale price of our common stock on Nasdaq on July 3, 2025, and after deducting offering commissions and estimated offering expenses payable by us, our as adjusted net tangible book value as of March 31, 2025 would have been approximately $397.7 million, or $17.03 per share. This represents an immediate increase in net tangible book value of $0.91 per share to our existing stockholders and immediate dilution in net tangible book value of $4.31 per share to investors purchasing our common stock in this offering at the assumed public offering price. The following table illustrates this dilution on a per share basis:

---

| | | |
|:---|:---|:---|
|  Assumed public offering price per share |  | $21.34 |
|  Net tangible book value per share as of March 31, 2025 | $16.12 |  |
|  Increase in net tangible book value per share attributable to new investors in this offering | 0.91 |  |
|  As adjusted net tangible book value per share as of March 31, 2025, after giving effect to this offering |  | 17.03 |
|  Dilution per share to new investors purchasing our common stock in this offering |  | $4.31 |

---

The above discussion and table are based on 18,671,229 shares of our common stock outstanding as of March 31, 2025, and excludes:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• 1,791,232 shares of common stock issuable upon the exercise of outstanding stock options at a weighted average
exercise price of $19.32 under our 2019 and 2024 Equity Incentive Plan as of March 31, 2025;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• 31,891 shares of common stock issuable upon the exercise of outstanding options at a weighted average exercise
price of $40.80 under the AVROBIO, Inc. 2018 Equity Incentive Plan as of March 31, 2025;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• 181,987 shares of common stock issuable upon the settlement of outstanding restricted stock units as of
March 31, 2025;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• 1,227,159 shares of common stock reserved for future issuance under our 2024 Equity Incentive Plan as of
March 31, 2025; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• 295,906 shares of common stock reserved for future issuance under our 2024 Employee Stock Purchase Plan as of
March 31, 2025.

The table above assumes for illustrative purposes that an aggregate of 4,686,036 shares of our common stock are sold under this prospectus supplement at a price of $21.34 per share, the last reported sale price of our common stock on Nasdaq on July 3, 2025, for aggregate gross proceeds of $100.0 million. The shares subject to the sales agreement are being sold from time to time at various prices. An increase of $1.00 per share in the price at which the shares are sold from the assumed public offering price of $21.34 per share shown in the table above, assuming all of our common stock in the aggregate amount of $100.0 million under this prospectus supplement is sold at that price, would increase our adjusted net tangible book value per share after the offering to $17.18 per share and would increase the dilution in net tangible book value per share to new investors in this offering to

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$5.16 per share, after deducting commissions and estimated aggregate offering expenses payable by us. decrease of $1.00 per share in the price at which the shares are sold from the assumed public offering price of $21.34 per share shown in the table above, assuming all of our common stock in the aggregate amount of $100.0 million under this prospectus supplement is sold at that price, would decrease our adjusted net tangible book value per share after the offering to $16.86 per share and would decrease the dilution in net tangible book value per share to new investors in this offering to $3.48 per share, after deducting commissions and estimated aggregate offering expenses payable by us. This information is supplied for illustrative purposes only and assumes no exercise of the options outstanding as of March 31, 2025 and no settlement of the restricted stock units outstanding as of March 31, 2025.

To the extent that options are exercised, restricted stock units vest or other shares are issued, investors purchasing our common stock in this offering may experience further dilution. In addition, we may choose to raise additional capital due to market conditions or strategic considerations even if we believe we have sufficient funds for our current or future operating plans. To the extent that additional capital is raised through the sale of equity or convertible debt securities, the issuance of these securities could result in further dilution to our stockholders.

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**PLAN OF DISTRIBUTION** 

We have entered into a sales agreement with TD Cowen, under which we may issue and sell from time to time up to $100,000,000 of our common stock through or to TD Cowen as our sales agent or principal. Sales of our common stock, if any, will be made in negotiated transactions, including block trades or block sales, or by any method permitted by law deemed to be an "at the market offering" as defined in Rule 415 under the Securities Act, including without limitation sales made through Nasdaq or on any other existing trading market for our common stock, or by any other method permitted by law. Sales pursuant to the sales agreement may be made through an affiliate of TD Cowen.

TD Cowen will offer our common stock subject to the terms and conditions of the sales agreement on a daily basis or as otherwise agreed upon by us and TD Cowen. We will designate the maximum amount of common stock to be sold through TD Cowen on a daily basis or otherwise determine such maximum amount together with TD Cowen. Subject to the terms and conditions of the sales agreement, TD Cowen will use its commercially reasonable efforts to sell on our behalf all of the shares of common stock requested to be sold by us. We may instruct TD Cowen not to sell common stock if the sales cannot be effected at or above the price designated by us in any such instruction. TD Cowen or we may suspend the offering of our common stock being made through TD Cowen under the sales agreement upon proper notice to the other party. TD Cowen and we each have the right, by giving written notice as specified in the sales agreement, to terminate the sales agreement in each party's sole discretion at any time.

The aggregate compensation payable to TD Cowen as sales agent equals up to 3.0% of the gross sales price of the shares sold through it pursuant to the sales agreement. We have also agreed to reimburse TD Cowen up to $75,000 of TD Cowen's actual outside legal expenses incurred by TD Cowen in connection with the execution of the sales agreement, in addition to certain ongoing disbursements of its legal counsel. We estimate that the total expenses of the offering payable by us, excluding commissions payable to TD Cowen under the sales agreement, will be approximately $350,000.

The remaining sales proceeds, after deducting any expenses payable by us and any transaction fees imposed by any governmental, regulatory, or self-regulatory organization in connection with the sales, will equal our net proceeds for the sale of such common stock.

TD Cowen will provide written confirmation to us following the close of trading on Nasdaq on each day in which common stock is sold through it as sales agent under the sales agreement. Each confirmation will include the number of shares of common stock sold through it as sales agent on that day, the volume weighted average price of the shares sold, the percentage of the daily trading volume and the net proceeds to us.

We will report at least quarterly the number of shares of common stock sold through TD Cowen under the sales agreement and the net proceeds to us in connection with the sales of common stock.

Settlement for sales of common stock will occur, unless the parties agree otherwise, on the first business day that is also a trading day following the date on which any sales were made in return for payment of the net proceeds to us. There is no arrangement for funds to be received in an escrow, trust or similar arrangement.

In connection with the sales of our common stock on our behalf, TD Cowen will be deemed to be an "underwriter" within the meaning of the Securities Act, and the compensation paid to TD Cowen will be deemed to be underwriting commissions or discounts. We have agreed in the sales agreement to provide indemnification and contribution to TD Cowen against certain liabilities, including liabilities under the Securities Act. As sales agent, TD Cowen will not engage in any transactions that stabilizes our common stock.

Our common stock is listed on Nasdaq and trades under the symbol "TECX." The transfer agent of our common stock is Computershare Trust Company, N.A.

TD Cowen and/or its affiliates have provided, and may in the future provide, various investment banking and other financial services for us for which services they have received and, may in the future receive, customary fees.

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**LEGAL MATTERS** 

The validity of the common stock offered by this prospectus supplement will be passed upon by Cooley LLP, New York, New York. TD Securities (USA) LLC is being represented in connection with this offering by Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C., Boston, Massachusetts.

**EXPERTS** 

The financial statements of Tectonic Therapeutic, Inc. as of December 31, 2024 and 2023, and for the years then ended, incorporated by reference in this prospectus supplement have been audited by Deloitte & Touche LLP, an independent registered public accounting firm, as stated in their report. Such financial statements are incorporated by reference in reliance upon the report of such firm, given their authority as experts in accounting and auditing.

**WHERE YOU CAN FIND MORE INFORMATION** 

This prospectus supplement is part of a registration statement we filed with the SEC. This prospectus supplement does not contain all of the information set forth in the registration statement and the exhibits to the registration statement. For further information with respect to us and the securities we are offering under this prospectus supplement, we refer you to the registration statement, the exhibits and schedules filed as a part of the registration statement, and the documents incorporated by reference in the registration statement. Statements in this prospectus supplement about these documents are summaries and each statement is qualified in all respects by reference to the document to which it refers. You should refer to the actual documents for a more complete description of the relevant matters. You may inspect a copy of the registration statement through the SEC's website, as provided below. Neither we nor any agent, underwriter or dealer has authorized any person to provide you with different information. We are not making an offer of these securities in any state where the offer is not permitted. You should not assume that the information in this prospectus supplement is accurate as of any date other than the date on the front page of this prospectus supplement, regardless of the time of delivery of this prospectus supplement or any sale of the securities offered by this prospectus supplement.

We file annual, quarterly and current reports, proxy statements and other information with the SEC. The SEC maintains a website that contains reports, proxy statements and other information regarding issuers that file electronically with the SEC, including Tectonic. The address of the SEC website is www.sec.gov.

We maintain a website at www.tectonictx.com. The information contained in, or that can be accessed through, our website is not incorporated by reference herein and is not part of this prospectus supplement.

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**INCORPORATION OF CERTAIN INFORMATION BY REFERENCE** 

The SEC allows us to "incorporate by reference" information that we file with it, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is an important part of this prospectus supplement. Information in this prospectus supplement supersedes information incorporated by reference that we filed with the SEC prior to the date of this prospectus supplement, while information that we file later with the SEC will automatically update and supersede the information in this prospectus supplement. We also incorporate by reference into this prospectus supplement the documents listed below and any future filings made by us with the SEC (other than Current Reports on Form 8-K or portions thereof furnished under Item 2.02 or Item 7.01 and exhibits filed pursuant to Item 9.01 on such form that are related to such items and other portions of documents that are furnished, but not filed, or are otherwise not incorporated into registration statements pursuant to applicable rules promulgated by the SEC) that are filed by us with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act (i) after the date of the filing of the registration statement of which this prospectus supplement is a part and prior to effectiveness of the registration statement, and (ii) after the effectiveness of the registration statement but prior to the termination of the offering of securities covered by this prospectus supplement:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• our Annual Report on Form 10-K for the year ended December 31, 2024,
filed with the SEC on [March 20, 2025](http://www.sec.gov/Archives/edgar/data/../../../ix?doc=/Archives/edgar/data/0001681087/000095017025042648/tecx-20241231.htm) and the information specifically incorporated by reference into our
Annual Report on Form 10-K for the year ended December 
31, 2024 from our Definitive Proxy Statement on Schedule 14A, filed with the SEC on [April 25, 2025](http://www.sec.gov/Archives/edgar/data/../../../ix?doc=/Archives/edgar/data/0001681087/000119312525096764/d949345ddef14a.htm) ;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• our Quarterly Report on Form 10-Q for the quarterly period ended
March 31, 2025, filed with the SEC on [May 8, 2025](http://www.sec.gov/Archives/edgar/data/../../../ix?doc=/Archives/edgar/data/0001681087/000095017025067037/tecx-20250331.htm) ;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• our Current Reports on Form 8-K (other than information furnished rather
than filed), filed with the SEC on [January 30, 2025](http://www.sec.gov/Archives/edgar/data/../../../ix?doc=/Archives/edgar/data/0001681087/000119312525016224/d817477d8k.htm) , [February 3, 2025](http://www.sec.gov/Archives/edgar/data/../../../ix?doc=/Archives/edgar/data/0001681087/000119312525018840/d843684d8k.htm) , [May 19, 2025](http://www.sec.gov/Archives/edgar/data/../../../ix?doc=/Archives/edgar/data/0001681087/000119312525122511/d939029d8k.htm) and [June 6, 2025](http://www.sec.gov/Archives/edgar/data/../../../ix?doc=/Archives/edgar/data/0001681087/000119312525137149/d31142d8k.htm) ; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the description of our common stock, which is registered under Section 
12 of the Exchange Act, described in [Exhibit 4.1](http://www.sec.gov/Archives/edgar/data/1681087/000095017025042648/tecx-ex4_1.htm) to our Annual Report on Form 10-K for the year ended
December 31, 2024, filed with the SEC on [March 20, 2025](http://www.sec.gov/Archives/edgar/data/../../../ix?doc=/Archives/edgar/data/0001681087/000095017025042648/tecx-20241231.htm) .

We will provide to each person, including any beneficial owner, to whom a prospectus supplement is delivered, without charge upon written or oral request, a copy of any or all of the documents that are incorporated by reference into this prospectus supplement but not delivered with the prospectus supplement, including exhibits which are specifically incorporated by reference into such documents. You should direct any requests for documents by writing or by telephoning us at the following address or phone number:

Tectonic Therapeutic, Inc.

Attention: Chief Financial Officer

490 Arsenal Way, Suite 210,

Watertown, Massachusetts

(339) 666-3320

Any statement contained herein or in a document incorporated or deemed to be incorporated by reference into this document will be deemed to be modified or superseded for purposes of the document to the extent that a statement contained in this document or any other subsequently filed document that is deemed to be incorporated by reference into this document modifies or supersedes the statement.

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**PROSPECTUS**![LOGO](g49849g04g04.jpg)

**$400,000,000** 

**Common Stock** 

**Preferred Stock** 

**Debt Securities** 

**Warrants** 

From time to time, we may offer and sell up to an aggregate amount of $400,000,000 of any combination of shares of our common stock, shares of our preferred stock, debt securities and warrants to purchase any of such securities in one or more offerings as described in this prospectus. We may also offer securities as may be issuable upon conversion, redemption, repurchase, exchange or exercise of any securities registered hereunder, including any applicable antidilution provisions.

This prospectus provides a general description of the securities we may offer. Each time we offer securities, we will specify in an accompanying prospectus supplement the terms of the securities being offered. We may also authorize one or more free writing prospectuses to be provided to you in connection with these offerings. The prospectus supplement and any related free writing prospectus may also add, update or change information contained in this prospectus. You should carefully read this prospectus, the applicable prospectus supplement and any related free writing prospectus, as well as any documents incorporated by reference, before you invest in any of the securities being offered.

**This prospectus may not be used to consummate a sale of any securities unless accompanied by a prospectus supplement.** 

Our common stock is traded on the Nasdaq Global Market under the symbol "TECX." On July 3, 2025, the last reported sale price of our common stock was $21.34 per share. The applicable prospectus supplement will contain information, where applicable, as to any other listing on the Nasdaq Global Market or any securities market or other exchange of the securities, if any, covered by the prospectus supplement.

We may offer and sell these securities directly to investors, through agents designated from time to time or to or through underwriters or dealers, on a continuous or delayed basis. For additional information on the methods of sale, you should refer to the section titled "Plan of Distribution" in this prospectus. If any agents or underwriters are involved in the sale of any securities with respect to which this prospectus is being delivered, the names of such agents or underwriters and any applicable fees, commissions, discounts or over-allotment options will be set forth in a prospectus supplement. The price to the public of such securities and the net proceeds we expect to receive from such sale will also be set forth in a prospectus supplement.

**Investing in our securities involves a high degree of risk. You should carefully review the risks and uncertainties described under the heading "[Risk Factors](#rom49849_3)" on page 4 of this prospectus as well as those contained in the applicable prospectus supplement and any related free writing prospectus, and under similar headings in the other documents that are incorporated by reference into this prospectus.** 

**NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR DETERMINED IF THIS PROSPECTUS IS TRUTHFUL OR COMPLETE. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.** 

**The date of this prospectus is July 15, 2025.** 

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**TABLE OF CONTENTS** 

---

| | |
|:---|:---|
|  | **Page** |
|  [ABOUT THIS PROSPECTUS](#rom49849_1) | ii |
|  [PROSPECTUS SUMMARY](#rom49849_2) | 1 |
|  [RISK FACTORS](#rom49849_3) | 4 |
|  [SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS](#rom49849_4) | 5 |
|  [USE OF PROCEEDS](#rom49849_5) | 6 |
|  [DESCRIPTION OF CAPITAL STOCK](#rom49849_6) | 7 |
|  [DESCRIPTION OF DEBT SECURITIES](#rom49849_7) | 11 |
|  [DESCRIPTION OF WARRANTS](#rom49849_8) | 18 |
|  [LEGAL OWNERSHIP OF SECURITIES](#rom49849_9) | 21 |
|  [PLAN OF DISTRIBUTION](#rom49849_10) | 24 |
|  [LEGAL MATTERS](#rom49849_11) | 26 |
|  [EXPERTS](#rom49849_12) | 26 |
|  [WHERE YOU CAN FIND MORE INFORMATION](#rom49849_13) | 26 |
|  [INCORPORATION OF CERTAIN INFORMATION BY REFERENCE](#rom49849_14) | 27 |

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**ABOUT THIS PROSPECTUS** 

This prospectus is a part of a registration statement on Form S-3 that we filed with the U.S. Securities and Exchange Commission ("SEC") utilizing a "shelf" registration process under the Securities Act of 1933, as amended (the "Securities Act"). Under this shelf registration process, we may offer and sell from time to time in one or more offerings the securities described in this prospectus up to a total dollar amount of $400,000,000.

This prospectus provides you with a general description of the securities we may offer. Each time we offer securities under this prospectus, we will provide a prospectus supplement that will contain specific information about the terms of these securities and offerings. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. The prospectus supplement and any related free writing prospectus that we may authorize to be provided to you may also add, update or change information contained in this prospectus or in any documents that we have incorporated by reference into this prospectus. You should read this prospectus, any applicable prospectus supplement and any related free writing prospectus, together with the information incorporated herein by reference as described under the heading "Incorporation of Certain Information by Reference," before investing in any of the securities offered.

**THIS PROSPECTUS MAY NOT BE USED TO CONSUMMATE A SALE OF SECURITIES UNLESS IT IS ACCOMPANIED BY A PROSPECTUS SUPPLEMENT.** 

Neither we, nor any agent, underwriter or dealer has authorized any person to give any information or to make any representation other than those contained or incorporated by reference in this prospectus, any applicable prospectus supplement or any related free writing prospectus prepared by or on behalf of us or to which we have referred you. We take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. This prospectus, any applicable supplement to this prospectus or any related free writing prospectus do not constitute an offer to sell or the solicitation of an offer to buy any securities other than the registered securities to which they relate, nor do this prospectus, any applicable supplement to this prospectus or any related free writing prospectus constitute an offer to sell or the solicitation of an offer to buy securities in any jurisdiction to any person to whom it is unlawful to make such offer or solicitation in such jurisdiction.

You should not assume that the information contained in this prospectus, any applicable prospectus supplement or any related free writing prospectus is accurate on any date subsequent to the date set forth on the front of the document or that any information we have incorporated by reference is correct on any date subsequent to the date of the document incorporated by reference, even though this prospectus, any applicable prospectus supplement or any related free writing prospectus is delivered, or securities are sold, on a later date.

This prospectus contains summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by the actual documents. Copies of some of the documents referred to herein have been filed, will be filed or will be incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you may obtain copies of those documents as described below under the heading "Where You Can Find More Information."

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**MARKET AND INDUSTRY DATA** 

Certain information contained in this document relates to or is based on studies, publications, surveys and other data obtained from third-party sources and our own internal estimates and research. While we believe these third-party sources to be reliable as of the date of this prospectus, we have not independently verified the market and industry data contained in this prospectus or the underlying assumptions relied on therein. Finally, while we believe our own internal research is reliable, such research has not been verified by any independent source. Notwithstanding the foregoing, we are liable for the information provided in this prospectus.

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**PROSPECTUS SUMMARY** 

This summary highlights selected information from this prospectus and does not contain all of the information that you need to consider in making your investment decision. You should carefully read the entire prospectus, the applicable prospectus supplement and any related free writing prospectus, including the risks of investing in our securities discussed under the heading "Risk Factors" contained in the applicable prospectus supplement and any related free writing prospectus, and under similar headings in the other documents that are incorporated by reference into this prospectus. You should also carefully read the information incorporated by reference into this prospectus, including our financial statements, and the exhibits to the registration statement of which this prospectus is a part.

Unless the context requires otherwise, references in this prospectus to the "Company," "Tectonic," "we," "us" and "our" refer to Tectonic Therapeutic, Inc.

**Company Overview** 

We are a clinical-stage biotechnology company focused on the discovery and development of therapeutic proteins and antibodies that modulate the activity of G-protein coupled receptors ("GPCRs"). The discovery of biologics that can modulate GPCRs has historically been quite challenging. We have developed a proprietary technology platform called GEODe<sup>™</sup>, with the aim of addressing these challenges to enable the discovery and development of GPCR-targeted biologic medicines that can modify the course of disease. We focus on areas of significant unmet medical need, often where therapeutic options are poor or nonexistent, as these are areas where new medicines have the potential to improve patient quality of life or extend duration of life.

Our lead asset, TX45, is an Fc-relaxin fusion molecule that activates the RXFP1 receptor, the GPCR target of the hormone, relaxin. In September 2024, we announced favorable results from a Phase 1a trial evaluating safety, tolerability and pharmacokinetic ("PK") and pharmacodynamic ("PD") properties for TX45. In this trial, TX45 was well-tolerated with no drug-related severe adverse events, no observed immunogenicity and demonstrated a favorable PK/PD relationship. Renal plasma flow was measured in each patient at several time points as a PD marker. This data was used to develop an exposure-response model which enabled the selection of doses for the APEX Phase 2 trial.

We are currently evaluating TX45 in a Phase 1b Part B hemodynamic clinical trial and in the APEX Phase 2 clinical trial. Part A of the TX45 Phase 1b hemodynamic clinical trial was a single intravenous dose, open-label clinical trial that evaluated the safety, tolerability, and acute hemodynamic effects of TX45 in subjects with Group 2 Pulmonary Hypertension in Heart Failure with preserved Ejection Fraction ("PH-HFpEF"). Part B which is still enrolling has a similar design but is being conducted in subjects with Group 2 Pulmonary Hypertension in Heart Failure with reduced Ejection Fraction ("PH-HFrEF"). APEX is a 24-week, placebo-controlled trial designed to evaluate the safety and efficacy of TX45 administered subcutaneously ("SC") in subjects with PH-HFpEF.

In May 2025, we announced the complete results from Part A of the Phase 1b clinical trial of TX45 in subjects with PH-HFpEF. The complete data from Part A confirmed the tolerability and hemodynamic effects of TX45 in patients with PH-HFpEF previously reported in the interim data. Based on the complete dataset, TX45 was well-tolerated in subjects with PH-HFpEF with no serious or severe adverse events. In the overall study population, TX45 achieved a 19.0% reduction in pulmonary capillary wedge pressure ("PCWP"), an endpoint known to correlate with exercise capacity, morbidity and mortality in patients with heart failure. In the subpopulation with combined pre- and post-capillary pulmonary hypertension who have an elevated Pulmonary Vascular Resistance ("PVR") and more severe disease, TX45 demonstrated >30% reduction in PVR, which along with PCWP is correlated to exercise capacity and mortality in this patient population. The Phase 1b

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Part A clinical trial enrolled a patient population and evaluated hemodynamic endpoints which are similar to the ongoing APEX Phase 2 clinical trial. We dosed our first patient in the APEX Phase 2 clinical trial in October 2024. Subjects will be randomized to 300 mg SC once monthly of TX45, 300 mg SC once every other week of TX45, or placebo. We expect topline trial results from the APEX clinical trial in 2026. Part B of the Phase 1b trial, which is assessing the acute hemodynamic effects of TX45 in subjects with Group 2 PH-HFrEF enrolled its first patient in the first half of 2025 with data expected to be announced in the second half of 2025.

We are also evaluating TX002100 ("TX2100") as our second development candidate for the treatment of Hereditary Hemorrhagic Telangiectasia ("HHT"), the second most common genetic bleeding disorder with no current approved therapy. TX2100 is a VHH-Fc fusion antagonist antibody that binds to an undisclosed GPCR target which plays a key role in pathogenic angiogenesis. A rodent surrogate of TX2100 demonstrated reduced arteriovenous malformation development and bleeding in an animal model of HHT. A 4-week non-human primate dose-range study with a functionally equivalent precursor to TX2100 showed no treatment-related toxicity observed at doses up to 100 mg/kg. A formulation supporting TX2100 SC dosing has been identified. Both Investigational New Drug ("IND")-enabling non-human primate good laboratory practices toxicology studies and technical development activities to generate good manufacturing practice drug supply and drug product for TX2100 started in the second quarter of 2025. We expect to initiate a Phase 1 clinical trial for TX2100 in the fourth quarter of 2025 or the first quarter of 2026, subject to the results of IND enabling studies.

**Corporate Information** 

We were incorporated under the laws of the State of Delaware in November 2015. Legacy Tectonic (as defined below) was incorporated under the laws of the State of Delaware in June 2019. On January 30, 2024, we entered into the Agreement and Plan of Merger and Reorganization (the "Merger Agreement") with Tectonic Operating Company, Inc. (previously Tectonic Therapeutic, Inc., referred to as "Legacy Tectonic") and Alpine Merger Subsidiary, Inc. ("Merger Sub"). Pursuant to the Merger Agreement, on June 20, 2024, Merger Sub merged with and into Legacy Tectonic, with Legacy Tectonic surviving as our wholly owned subsidiary (the "Merger"). In connection with the completion of the Merger, we changed our name from "AVROBIO, Inc." to "Tectonic Therapeutic, Inc." Our principal executive office is located at 490 Arsenal Way, Suite 210, Watertown, Massachusetts 02472, and our telephone number is (339) 666-3320. Our website address is www.tectonictx.com. We do not incorporate the information on or accessible through our website into this prospectus, and you should not consider any information on, or that can be accessed through, our website as part of this prospectus. Our common stock is listed on Nasdaq under the symbol "TECX."

This prospectus contains references to our trademarks and to trademarks belonging to other entities. Solely for convenience, trademarks and trade names referred to in this prospectus, including logos, artwork and other visual displays, may appear without the <sup>®</sup> or TM symbols, but such references are not intended to indicate, in any way, that their respective owners will not assert, to the fullest extent under applicable law, their rights thereto. We do not intend our use or display of other companies' trade names or trademarks to imply a relationship with, or endorsement or sponsorship of us by, any other companies.

**Implications of Being a Smaller Reporting Company** 

We are currently a "smaller reporting company" as defined in Item 10(f)(1) of Regulation S-K. Smaller reporting companies may take advantage of certain reduced disclosure obligations, including, among other things, providing only two years of audited financial statements. We may continue to be a smaller reporting company if either (i) the market value of our stock held by non-affiliates is less than $250.0 million or (ii) our annual revenue was less than $100.0 million during the most recently completed fiscal year and the market value of our stock held by non-affiliates is less than $700.0 million. Specifically, as a smaller reporting company we may choose to present only the two most recent fiscal years of audited financial statements in our Annual Report on Form 10-K and have reduced disclosure obligations regarding executive compensation.

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**The Securities We May Offer** 

We may offer shares of our common stock, shares of our preferred stock, debt securities and warrants to purchase any of such securities, up to a total aggregate amount of $400,000,000, from time to time in one or more offerings under this prospectus, together with any applicable prospectus supplement and any related free writing prospectus, at prices and on terms to be determined by market conditions at the time of the relevant offering. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities under this prospectus, we will provide a prospectus supplement that will describe the specific amounts, prices and other important terms of the securities, including, to the extent applicable:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• designation or classification;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• aggregate principal amount or aggregate offering price;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• maturity, if applicable;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• original issue discount, if any;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• rates and times of payment of interest or dividends, if any;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• redemption, conversion, exchange or sinking fund terms, if any;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• conversion or exchange prices or rates, if any, and, if applicable, any provisions for changes to or adjustments
in the conversion or exchange prices or rates and in the securities or other property receivable upon conversion or exchange;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• ranking, if applicable;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• restrictive covenants, if any;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• voting or other rights, if any; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• important U.S. federal income tax considerations.

The prospectus supplement and any related free writing prospectus that we may authorize to be provided to you may also add, update or change information contained in this prospectus or in documents we have incorporated by reference. However, no prospectus supplement or free writing prospectus will offer a security that is not registered and described in this prospectus at the time of the effectiveness of the registration statement of which this prospectus is a part.

**This prospectus may not be used to consummate a sale of securities unless it is accompanied by a prospectus supplement.** 

We may sell the securities directly to investors or through underwriters, dealers or agents. We, and our underwriters or agents, reserve the right to accept or reject all or part of any proposed purchase of securities. If we do offer securities through underwriters or agents, we will include in the applicable prospectus supplement:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the names of those underwriters or agents;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• applicable fees, discounts and commissions to be paid to them;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• details regarding over-allotment options, if any; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the estimated net proceeds to us.

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**RISK FACTORS** 

Investing in our securities involves a high degree of risk. You should carefully review the risks and uncertainties described under the heading "Risk Factors" contained in the applicable prospectus supplement and any related free writing prospectus, and under similar headings in our most recent Annual Report on Form 10-K and any subsequent Quarterly Reports on Form 10-Q or Current Reports on Form 8-K we file after the date of this prospectus, and all other information contained in or incorporated by reference into this prospectus and the applicable prospectus supplement and any related free writing prospectus, before deciding whether to purchase any of the securities being registered pursuant to the registration statement of which this prospectus is a part. Each of the risk factors could adversely affect our business, operating results and financial condition, as well as adversely affect the value of an investment in our securities, and the occurrence of any of these risks might cause you to lose all or part of your investment. Additional risks not presently known to us or that we currently believe are immaterial may also significantly impair our business operations.

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**SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS** 

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• our strategies, prospects, plans, expectations or objectives of management for our future operations;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• our progress, scope or timing of the development of our product candidates;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• our expectations surrounding the potential safety, efficacy, and regulatory and clinical progress of TX45, TX2100
and any other product candidates, and our anticipated milestones and timing therefor;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the benefits that may be derived from any of our future products, if approved, or the commercial or market
opportunity with respect to any of our future products, if approved;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• our ability to protect our intellectual property rights;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• our anticipated operations, financial position, ability to raise capital to fund our operations, revenues, costs
or expenses;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the effects of macroeconomic and geopolitical conditions and unforeseeable events;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• our expectations regarding the use of proceeds from offerings of our securities under this prospectus;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• other factors set forth in documents filed, or to be filed, with the SEC; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the statements regarding our future economic conditions or performance, statements of belief and any statement of
assumptions underlying any of the foregoing.

In some cases, you can identify forward-looking statements by terms such as "anticipates," "believes," "could," "estimates," "expects," "goal," "intends," "may," "plans," "potential," "predicts," "projects," "should," "will," "would," the negative of these words and words or similar expressions intended to identify forward-looking statements. These statements reflect our views as of the date on which they were made with respect to future events and are based on assumptions and subject to risks and uncertainties. The underlying information and expectations are likely to change over time. In addition, statements that "we believe" and similar statements reflect our beliefs and opinions on the relevant subject. These statements are based upon information available to us as of the date the statement is made, and while we believe such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that we have conducted an exhaustive inquiry into, or review of, all potentially available relevant information. These statements are inherently uncertain and you are cautioned not to unduly rely upon these statements.

Given these uncertainties, you should not place undue reliance on these forward-looking statements as actual events or results may differ materially from those projected in the forward-looking statements due to various factors, including, but not limited to, those set forth under the heading "Risk Factors" in any applicable prospectus supplement, the documents incorporated by reference therein or any free writing prospectus that we authorized. These forward-looking statements represent our estimates and assumptions only as of the date of the document containing the applicable statement. Our actual future results may be materially different from what we expect. We qualify all of the forward-looking statements contained in this prospectus, in the documents incorporated by reference herein and in any prospectus supplement by these cautionary statements. Unless required by law, we undertake no obligation to update or revise any forward-looking statements to reflect new information or future events or developments. Thus, you should not assume that our silence over time means that actual events are bearing out as expressed or implied in such forward-looking statements. Before deciding to purchase our securities, you should carefully consider the risk factors discussed in this prospectus, any accompanying prospectus supplement or free writing prospectus and in the documents incorporated by reference, in addition to the other information set forth in this prospectus, any accompanying prospectus supplement or free writing prospectus and in the documents incorporated by reference.

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**USE OF PROCEEDS** 

Except as described in any prospectus supplement or in any related free writing prospectus that we may authorize to be provided to you, we currently intend to use the net proceeds from the sale of securities under this prospectus for continued clinical development of pipeline products, working capital and other general corporate purposes. We may also use the net proceeds to in-license, acquire or invest in complementary businesses, technologies, products or assets. However, we have no current commitments or obligations to do so. As of the date of this prospectus, we cannot specify with certainty all of the particular uses of the net proceeds, if any, from the sale of securities under this prospectus. Accordingly, we will retain broad discretion over the use of any such proceeds. We will set forth in the prospectus supplement our intended use for the net proceeds to be received from the sale of any securities. Pending the use of the net proceeds from the sale of securities under this prospectus as described above, we intend to invest the net proceeds in investment-grade, interest-bearing instruments.

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**DESCRIPTION OF CAPITAL STOCK** 

*The following description of our capital stock and provisions of our fourth amended and restated certificate of incorporation (the "charter") and amended and restated by-laws (the "by-laws") are summaries and are qualified by reference to such charter and by-laws and applicable provisions of the General Corporation Law of the State of Delaware (the "DGCL"). Copies of these documents are filed as exhibits to the registration statement of which this prospectus forms a part.* 

**Authorized Capital Stock** 

Our authorized capital stock consists of 150,000,000 shares of common stock, par value $0.0001 per share (the "common stock"), and 10,000,000 shares of preferred stock, par value $0.0001 per share (the "preferred stock").

**Common Stock** 

*Dividends* 

Holders of our common stock are entitled to receive dividends ratably, if any, as may be declared by our board of directors out of legally available funds, subject to any preferential dividend rights of any our preferred stock then outstanding.

*Voting* 

Holders of our common stock are entitled to one vote for each share of our common stock held of record for the election of directors of the Company and on all matters submitted to a vote of the stockholders. The holders of our common stock do not have any cumulative voting rights.

*Distributions on Liquidation* 

In the event of our dissolution, liquidation or winding up, holders of our common stock are entitled to share ratably in all assets remaining after payment of all debts and other liabilities and any liquidation preference of any outstanding preferred stock. All outstanding shares are fully paid and non-assessable.

*Other Rights* 

Holders of our common stock are not entitled to preemptive, subscription, redemption or conversion rights, and no sinking fund provisions are applicable to our common stock.

**Preferred Stock** 

Our charter provides for 10,000,000 authorized shares of preferred stock. The existence of authorized but unissued shares of preferred stock may enable our board of directors to discourage an attempt to obtain control of the Company by means of a merger, tender offer, proxy contest or otherwise. For example, if in the due exercise of its fiduciary obligations, our board of directors were to determine that a takeover proposal is not in the best interests of our stockholders, our board of directors could cause shares of preferred stock to be issued without stockholder approval in one or more private offerings or other transactions that might dilute the voting or other rights of the proposed acquirer or insurgent stockholder or stockholder group. In this regard, our charter grants our board of directors broad power to establish the rights and preferences of authorized and unissued shares of preferred stock. The issuance of shares of preferred stock could decrease the amount of earnings and assets available for distribution to holders of shares of common stock. The issuance may also adversely affect the rights and powers, including voting rights, of these holders and may have the effect of delaying, deterring or preventing a change in control of the Company.

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**Anti-Takeover Effects of Delaware Law and Provisions of Our Charter and By-laws** 

Certain provisions of the DGCL and of our charter and by-laws could have the effect of delaying, deferring or discouraging another party from acquiring control of us. These provisions, which are summarized below, are expected to discourage certain types of coercive takeover practices and inadequate takeover bids and, as a consequence, they might also inhibit temporary fluctuations in the market price of our common stock that often result from actual or rumored hostile takeover attempts. These provisions are also designed in part to encourage anyone seeking to acquire control of us to first negotiate with our board of directors. These provisions might also have the effect of preventing changes in our management. It is possible that these provisions could make it more difficult to accomplish transactions that stockholders might otherwise deem to be in their best interests. However, we hold that the advantages gained by protecting our ability to negotiate with any unsolicited and potentially unfriendly acquirer outweigh the disadvantages of discouraging such proposals, including those priced above the then-current market value of our common stock, because, among other reasons, the negotiation of such proposals could improve their terms.

*Delaware Anti-Takeover Statute* 

We are subject to the provisions of Section 203 of the DGCL ("Section 203"). In general, Section 203 prohibits a publicly held Delaware corporation from engaging in a "business combination" with an "interested stockholder" for a three-year period following the date that this stockholder becomes an interested stockholder, unless the business combination is approved in a prescribed manner. Under Section 203, a business combination between a corporation and an interested stockholder is prohibited unless it satisfies one of the following conditions:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• before the stockholder became interested, the board of directors approved either the business combination or the
transaction which resulted in the stockholder becoming an interested stockholder;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• upon consummation of the transaction which resulted in the stockholder becoming an interested stockholder, the
interested stockholder owned at least 85% of the voting stock of the corporation outstanding at the time the transaction commenced, excluding for purposes of determining the voting stock outstanding shares owned by persons who are directors and also
officers, and employee stock plans, in some instances, but not the outstanding voting stock owned by the interested stockholder; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• at or after the time the stockholder became interested, the business combination was approved by the board of
directors and authorized at an annual or special meeting of the stockholders by the affirmative vote of at least two-thirds of the outstanding voting stock which is not owned by the interested stockholder.

Section 203 defines a business combination to include:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• any merger or consolidation involving the corporation or any direct or indirect majority-owned subsidiary of the
corporation and the interested stockholder;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• any sale, transfer, lease, pledge or other disposition (in one or more transactions) involving the interested
stockholder of 10% or more of either the aggregate market value of all (i) the assets of the corporation or (ii) the outstanding capital stock of the corporation, involving the interested stockholder;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• subject to exceptions, any transaction that results in the issuance or transfer by the corporation or by any
direct or indirect majority-owned subsidiary of the corporation of any stock of the corporation or any subsidiary to the interested stockholder;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• subject to exceptions, any transaction involving the corporation or any direct or indirect majority-owned
subsidiary of the corporation that has the effect of increasing the proportionate share of the stock of any class or series of the corporation or of any subsidiary beneficially owned by the interested stockholder; and

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the receipt by the interested stockholder of the benefit of any loans, advances, guarantees, pledges or other
financial benefits provided by or through the corporation or any direct or indirect majority-owned subsidiary.

In general, Section 203 defines an "interested stockholder" as any entity or person beneficially owning 15% or more of the outstanding voting stock of the corporation and any entity or person that is an affiliate or associate of the corporation and who beneficially owned 15% or more of the outstanding voting stock of the corporation at any time within the three year period immediately prior to the date of determining whether such entity or person is an interested stockholder, and any affiliate or associate of that entity or person.

*Board Composition and Filling Vacancies* 

Our charter provides for the division of our board of directors into three classes serving staggered three-year terms, with one class being elected each year. Our charter also provides that directors may be removed only for cause and then only by the affirmative vote of the holders of two-thirds or more of the shares then entitled to vote at an election of directors. Furthermore, any vacancy on our board of directors, however occurring, including a vacancy resulting from an increase in the size of our board of directors, may only be filled by the affirmative vote of a majority of directors then in office even if less than a quorum. The classification of directors, together with the limitations on removal of directors and treatment of vacancies, has the effect of making it more difficult for stockholders to change the composition of our board of directors.

*No Written Consent of Stockholders* 

Our charter provides that all stockholder actions are required to be taken by a vote of the stockholders at an annual or special meeting, and that stockholders may not take any action by written consent in lieu of a meeting. This limit may lengthen the amount of time required to take stockholder actions and would prevent the amendment of our by-laws or removal of directors by stockholders without holding a meeting of stockholders.

*Meetings of Stockholders* 

Our charter and by-laws provide that only a majority of the members of our board of directors then in office may call special meetings of stockholders and only those matters set forth in the notice of the special meeting may be considered or acted upon at a special meeting of stockholders. Our by-laws limit the business that may be conducted at an annual meeting of stockholders to those matters properly brought before the meeting.

*Advance Notice Requirements* 

Our by-laws establish advance notice procedures with regard to stockholder proposals relating to the nomination of candidates for election as directors or new business to be brought before meetings of Company stockholders. These procedures provide that notice of stockholder proposals must be timely given in writing to our corporate secretary prior to the meeting at which the action is to be taken. Generally, to be timely, notice must be received at our principal executive offices not less than 90 days nor more than 120 days prior to the first anniversary date of the annual meeting for the preceding year. Our by-laws specify the requirements as to form and content of all stockholders' notices. These requirements may preclude stockholders from bringing matters before the stockholders at an annual or special meeting.

*Choice of Forum* 

Our by-laws provide that, unless we consent in writing to the selection of an alternative forum, the Court of Chancery of the State of Delaware will be the sole and exclusive forum for any state law claim for: (1) any derivative action or proceeding brought on our behalf; (2) any action asserting a claim of breach of or based on a fiduciary duty owed by any of our current or former directors, officers or other employees to us or our

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In addition, our by-laws contain a provision by virtue of which unless we consent in writing to the selection of an alternative forum, the United States District Court for the District of Massachusetts will be the exclusive forum for resolving any complaint asserting a cause of action arising under the Securities Act.

**Transfer Agent and Registrar** 

The transfer agent and registrar for our common stock is Computershare Trust Company, N.A. The transfer agent and registrar's address is 150 Royall Street, Canton, MA 02021, and its telephone number is (800) 962-4284.

**Listing on the Nasdaq Global Market** 

Our common stock is listed on the Nasdaq Global Market under the symbol "TECX."

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**DESCRIPTION OF DEBT SECURITIES** 

We may issue debt securities from time to time, in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. While the terms we have summarized below will apply generally to any debt securities that we may offer under this prospectus, we will describe the particular terms of any debt securities that we may offer in more detail in the applicable prospectus supplement. The terms of any debt securities offered under a prospectus supplement may differ from the terms described below. Unless the context requires otherwise, whenever we refer to the indenture, we also are referring to any supplemental indentures that specify the terms of a particular series of debt securities.

We will issue the debt securities under the indenture that we will enter into with the trustee named in the indenture. The indenture will be qualified under the Trust Indenture Act of 1939, as amended (the "Trust Indenture Act"). We have filed the form of indenture as an exhibit to the registration statement of which this prospectus is a part, and supplemental indentures and forms of debt securities containing the terms of the debt securities being offered will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports that we file with the SEC.

The following summary of material provisions of the debt securities and the indenture is subject to, and qualified in its entirety by reference to, all of the provisions of the indenture applicable to a particular series of debt securities. We urge you to read the applicable prospectus supplements and any related free writing prospectuses related to the debt securities that we may offer under this prospectus, as well as the complete indenture that contains the terms of the debt securities.

**General** 

The indenture does not limit the amount of debt securities that we may issue. It provides that we may issue debt securities up to the principal amount that we may authorize and may be in any currency or currency unit that we may designate. Except for the limitations on consolidation, merger and sale of all or substantially all of our assets contained in the indenture, the terms of the indenture do not contain any covenants or other provisions designed to give holders of any debt securities protection against changes in our operations, financial condition or transactions involving us.

We may issue the debt securities issued under the indenture as "discount securities," which means they may be sold at a discount below their stated principal amount. These debt securities, as well as other debt securities that are not issued at a discount, may be issued with "original issue discount" ("OID"), for U.S. federal income tax purposes because of interest payment and other characteristics or terms of the debt securities. Material U.S. federal income tax considerations applicable to debt securities issued with OID will be described in more detail in any applicable prospectus supplement.

We will describe in the applicable prospectus supplement the terms of the series of debt securities being offered, including:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the title of the series of debt securities;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• any limit upon the aggregate principal amount that may be issued;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the maturity date or dates;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the form of the debt securities of the series;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the applicability of any guarantees;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• whether or not the debt securities will be secured or unsecured, and the terms of any secured debt;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• whether the debt securities rank as senior debt, senior subordinated debt, subordinated debt or any combination
thereof, and the terms of any subordination;

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• if the price (expressed as a percentage of the aggregate principal amount thereof) at which such debt securities
will be issued is a price other than the principal amount thereof, the portion of the principal amount thereof payable upon declaration of acceleration of the maturity thereof, or if applicable, the portion of the principal amount of such debt
securities that is convertible into another security or the method by which any such portion shall be determined;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the interest rate or rates, which may be fixed or variable, or the method for determining the rate and the date
interest will begin to accrue, the dates interest will be payable and the regular record dates for interest payment dates or the method for determining such dates;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• our right, if any, to defer payment of interest and the maximum length of any such deferral period;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• if applicable, the date or dates after which, or the period or periods during which, and the price or prices at
which, we may, at our option, redeem the series of debt securities pursuant to any optional or provisional redemption provisions and the terms of those redemption provisions;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the date or dates, if any, on which, and the price or prices at which we are obligated, pursuant to any mandatory
sinking fund or analogous fund provisions or otherwise, to redeem, or at the holder's option to purchase, the series of debt securities and the currency or currency unit in which the debt securities are payable;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the denominations in which we will issue the series of debt securities, if other than denominations of $1,000 and
any integral multiple thereof;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• any and all terms, if applicable, relating to any auction or remarketing of the debt securities of that series
and any security for our obligations with respect to such debt securities and any other terms which may be advisable in connection with the marketing of debt securities of that series;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• whether the debt securities of the series shall be issued in whole or in part in the form of a global security or
securities; the terms and conditions, if any, upon which such global security or securities may be exchanged in whole or in part for other individual securities; and the depositary for such global security or securities;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• if applicable, the provisions relating to conversion or exchange of any debt securities of the series and the
terms and conditions upon which such debt securities will be so convertible or exchangeable, including the conversion or exchange price, as applicable, or how it will be calculated and may be adjusted, any mandatory or optional (at our option or the
holders' option) conversion or exchange features, the applicable conversion or exchange period and the manner of settlement for any conversion or exchange;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• if other than the full principal amount thereof, the portion of the principal amount of debt securities of the
series which shall be payable upon declaration of acceleration of the maturity thereof;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• additions to or changes in the covenants applicable to the particular debt securities being issued, including,
among others, the consolidation, merger or sale covenant;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• additions to or changes in the events of default with respect to the securities and any change in the right of
the trustee or the holders to declare the principal, premium, if any, and interest, if any, with respect to such securities to be due and payable;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• additions to or changes in or deletions of the provisions relating to covenant defeasance and legal defeasance;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• additions to or changes in the provisions relating to satisfaction and discharge of the indenture;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• additions to or changes in the provisions relating to the modification of the indenture both with and without the
consent of holders of debt securities issued under the indenture;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the currency of payment of debt securities if other than U.S. dollars and the manner of determining the
equivalent amount in U.S. dollars;

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• whether interest will be payable in cash or additional debt securities at our or the holders' option and the
terms and conditions upon which the election may be made;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the terms and conditions, if any, upon which we will pay amounts in addition to the stated interest, premium, if
any, and principal amounts of the debt securities of the series to any holder that is not a "United States person" for federal tax purposes;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• any restrictions on transfer, sale or assignment of the debt securities of the series; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• any other specific terms, preferences, rights or limitations of, or restrictions on, the debt securities, any
other additions or changes in the provisions of the indenture, and any terms that may be required by us or advisable under applicable laws or regulations.

**Conversion or Exchange Rights** 

We will set forth in the applicable prospectus supplement the terms on which a series of debt securities may be convertible into or exchangeable for our common stock or our other securities. We will include provisions as to settlement upon conversion or exchange and whether conversion or exchange is mandatory, at the option of the holder or at our option. We may include provisions pursuant to which the number of shares of our common stock or our other securities that the holders of the series of debt securities receive would be subject to adjustment.

**Consolidation, Merger or Sale** 

Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the indenture will not contain any covenant that restricts our ability to merge or consolidate, or sell, convey, transfer or otherwise dispose of our assets as an entirety or substantially as an entirety. However, any successor to or acquirer of such assets (other than a subsidiary of ours) must assume all of our obligations under the indenture or the debt securities, as appropriate.

**Events of Default under the Indenture** 

Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the following are events of default under the indenture with respect to any series of debt securities that we may issue:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• if we fail to pay any installment of interest on any series of debt securities, as and when the same shall become
due and payable, and such default continues for a period of 90 days; provided, however, that a valid extension of an interest payment period by us in accordance with the terms of any indenture supplemental thereto shall not constitute a default in
the payment of interest for this purpose;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• if we fail to pay the principal of, or premium, if any, on any series of debt securities as and when the same
shall become due and payable whether at maturity, upon redemption, by declaration or otherwise, or in any payment required by any sinking or analogous fund established with respect to such series; provided, however, that a valid extension of the
maturity of such debt securities in accordance with the terms of any indenture supplemental thereto shall not constitute a default in the payment of principal or premium, if any;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• if we fail to observe or perform any other covenant or agreement contained in the debt securities or the
indenture, other than a covenant specifically relating to another series of debt securities, and our failure continues for 90 days after we receive written notice of such failure, requiring the same to be remedied and stating that such is a notice
of default thereunder, from the trustee or holders of at least 25% in aggregate principal amount of the outstanding debt securities of the applicable series; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• if specified events of bankruptcy, insolvency or reorganization occur.

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If an event of default with respect to debt securities of any series occurs and is continuing, other than an event of default specified in the last bullet point above, the trustee or the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series, by notice to us in writing, and to the trustee if notice is given by such holders, may declare the unpaid principal of, premium, if any, and accrued interest, if any, due and payable immediately. If an event of default specified in the last bullet point above occurs with respect to us, the principal amount of and accrued interest, if any, of each issue of debt securities then outstanding shall be due and payable without any notice or other action on the part of the trustee or any holder.

The holders of a majority in principal amount of the outstanding debt securities of an affected series may waive any default or event of default with respect to the series and its consequences, except defaults or events of default regarding payment of principal, premium, if any, or interest, unless we have cured the default or event of default in accordance with the indenture. Any waiver shall cure the default or event of default.

Subject to the terms of the indenture, if an event of default under an indenture shall occur and be continuing, the trustee will be under no obligation to exercise any of its rights or powers under such indenture at the request or direction of any of the holders of the applicable series of debt securities, unless such holders have offered the trustee reasonable indemnity. The holders of a majority in principal amount of the outstanding debt securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the trustee, or exercising any trust or power conferred on the trustee, with respect to the debt securities of that series, provided that:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the direction so given by the holder is not in conflict with any law or the applicable indenture; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• subject to its duties under the Trust Indenture Act, the trustee need not take any action that might involve it
in personal liability or might be unduly prejudicial to the holders not involved in the proceeding.

A holder of the debt securities of any series will have the right to institute a proceeding under the indenture or to appoint a receiver or trustee, or to seek other remedies only if:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the holder has given written notice to the trustee of a continuing event of default with respect to that series;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series have
made written request;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• such holders have offered to the trustee indemnity satisfactory to it against the costs, expenses and liabilities
to be incurred by the trustee in compliance with the request; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the trustee does not institute the proceeding, and does not receive from the holders of a majority in aggregate
principal amount of the outstanding debt securities of that series other conflicting directions within 90 days after the notice, request and offer.

These limitations do not apply to a suit instituted by a holder of debt securities if we default in the payment of the principal, premium, if any, or interest on, the debt securities.

We will periodically file statements with the trustee regarding our compliance with specified covenants in the indenture.

**Modification of Indenture; Waiver** 

We and the trustee may change an indenture without the consent of any holders with respect to specific matters:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• to cure any ambiguity, defect or inconsistency in the indenture or in the debt securities of any series;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• to comply with the provisions described above under "Description of Debt Securities—Consolidation,
Merger or Sale;"

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• to provide for uncertificated debt securities in addition to or in place of certificated debt securities;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• to add to our covenants, restrictions, conditions or provisions such new covenants, restrictions, conditions or
provisions for the benefit of the holders of all or any series of debt securities, to make the occurrence, or the occurrence and the continuance, of a default in any such additional covenants, restrictions, conditions or provisions an event of
default or to surrender any right or power conferred upon us in the indenture;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• to add to, delete from or revise the conditions, limitations, and restrictions on the authorized amount, terms,
or purposes of issue, authentication and delivery of debt securities, as set forth in the indenture;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• to make any change that does not adversely affect the interests of any holder of debt securities of any series in
any material respect;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• to provide for the issuance of and establish the form and terms and conditions of the debt securities of any
series as provided above under "Description of Debt Securities—General" to establish the form of any certifications required to be furnished pursuant to the terms of the indenture or any series of debt securities, or to add to the
rights of the holders of any series of debt securities;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• to evidence and provide for the acceptance of appointment under any indenture by a successor trustee; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• to comply with any requirements of the SEC in connection with the qualification of any indenture under the Trust
Indenture Act.

In addition, under the indenture, the rights of holders of a series of debt securities may be changed by us and the trustee with the written consent of the holders of at least a majority in aggregate principal amount of the outstanding debt securities of each series that is affected. However, unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, we and the trustee may make the following changes only with the consent of each holder of any outstanding debt securities affected:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• extending the fixed maturity of any debt securities of any series;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• reducing the principal amount, reducing the rate of or extending the time of payment of interest, or reducing any
premium payable upon the redemption of any series of any debt securities; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• reducing the percentage of debt securities, the holders of which are required to consent to any amendment,
supplement, modification or waiver.

**Discharge** 

The indenture provides that we can elect to be discharged from our obligations with respect to one or more series of debt securities, except for specified obligations, including obligations to:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• provide for payment;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• register the transfer or exchange of debt securities of the series;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• replace stolen, lost or mutilated debt securities of the series;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• pay principal of and premium and interest on any debt securities of the series;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• maintain paying agencies;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• hold monies for payment in trust;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• recover excess money held by the trustee;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• compensate and indemnify the trustee; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• appoint any successor trustee.

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In order to exercise our rights to be discharged, we must deposit with the trustee money or government obligations sufficient to pay all the principal of, any premium, if any, and interest on, the debt securities of the series on the dates payments are due.

**Form, Exchange and Transfer** 

We will issue the debt securities of each series only in fully registered form without coupons and, unless we provide otherwise in the applicable prospectus supplement, in denominations of $1,000 and any integral multiple thereof. The indenture provides that we may issue debt securities of a series in temporary or permanent global form and as book-entry securities that will be deposited with, or on behalf of, The Depository Trust Company ("DTC"), or another depositary named by us and identified in the applicable prospectus supplement with respect to that series. To the extent the debt securities of a series are issued in global form and as book-entry, a description of terms relating to any book-entry securities will be set forth in the applicable prospectus supplement.

At the option of the holder, subject to the terms of the indenture and the limitations applicable to global securities described in the applicable prospectus supplement, the holder of the debt securities of any series can exchange the debt securities for other debt securities of the same series, in any authorized denomination and of like tenor and aggregate principal amount.

Subject to the terms of the indenture and the limitations applicable to global securities set forth in the applicable prospectus supplement, holders of the debt securities may present the debt securities for exchange or for registration of transfer, duly endorsed or with the form of transfer endorsed thereon duly executed if so required by us or the security registrar, at the office of the security registrar or at the office of any transfer agent designated by us for this purpose. Unless otherwise provided in the debt securities that the holder presents for transfer or exchange, we will impose no service charge for any registration of transfer or exchange, but we may require payment of any taxes or other governmental charges.

We will name in the applicable prospectus supplement the security registrar, and any transfer agent in addition to the security registrar, that we initially designate for any debt securities. We may at any time designate additional transfer agents or rescind the designation of any transfer agent or approve a change in the office through which any transfer agent acts, except that we will be required to maintain a transfer agent in each place of payment for the debt securities of each series.

If we elect to redeem the debt securities of any series, we will not be required to:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• issue, register the transfer of, or exchange any debt securities of that series during a period beginning at the
opening of business 15 days before the day of mailing of a notice of redemption of any debt securities that may be selected for redemption and ending at the close of business on the day of the mailing; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• register the transfer or exchange of any debt securities so selected for redemption, in whole or in part, except
the unredeemed portion of any debt securities we are redeeming in part.

**Information Concerning the Trustee** 

The trustee, other than during the occurrence and continuance of an event of default under an indenture, undertakes to perform only those duties as are specifically set forth in the applicable indenture. Upon an event of default under an indenture, the trustee must use the same degree of care as a prudent person would exercise or use in the conduct of his or her own affairs. Subject to this provision, the trustee is under no obligation to exercise any of the powers given to it by the indenture at the request of any holder of debt securities unless it is offered reasonable security and indemnity against the costs, expenses and liabilities that it might incur.

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**Payment and Paying Agents** 

Unless we otherwise indicate in the applicable prospectus supplement, we will make payment of the interest on any debt securities on any interest payment date to the person in whose name the debt securities, or one or more predecessor securities, are registered at the close of business on the regular record date for the interest.

We will pay the principal of and any premium and interest on the debt securities of a particular series at the office of the paying agents designated by us, except that unless we otherwise indicate in the applicable prospectus supplement, we will make interest payments by check that we will mail to the holder or by wire or ACH transfer to certain holders. Unless we otherwise indicate in the applicable prospectus supplement, we will designate the corporate trust office of the trustee as our sole paying agent for payments with respect to debt securities of each series. We will name in the applicable prospectus supplement any other paying agents that we initially designate for the debt securities of a particular series. We will maintain a paying agent in each place of payment for the debt securities of a particular series.

All money we pay to a paying agent or the trustee for the payment of the principal of or any premium or interest on any debt securities that remains unclaimed at the end of two years after such principal, premium or interest has become due and payable will be repaid to us, and the holder of the debt security thereafter may look only to us for payment thereof.

**Governing Law** 

The indenture and the debt securities will be governed by and construed in accordance with the internal laws of the State of New York, except to the extent that the Trust Indenture Act is applicable.

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**DESCRIPTION OF WARRANTS** 

The following description, together with the additional information we may include in any applicable prospectus supplements and free writing prospectuses, summarizes the material terms and provisions of the warrants that we may offer under this prospectus, which may consist of warrants to purchase common stock, preferred stock or debt securities and may be issued in one or more series. Warrants may be issued independently or together with common stock, preferred stock or debt securities offered by any prospectus supplement and may be attached to or separate from those securities. While the terms we have summarized below will apply generally to any warrants that we may offer under this prospectus, we will describe the particular terms of any series of warrants that we may offer in more detail in the applicable prospectus supplement and any applicable free writing prospectus. The terms of any warrants offered under a prospectus supplement may differ from the terms described below. However, no prospectus supplement will fundamentally change the terms that are set forth in this prospectus or offer a security that is not registered and described in this prospectus at the time of its effectiveness.

We have filed forms of the warrant agreements as exhibits to the registration statement of which this prospectus is a part. We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of warrant agreement, if any, including a form of warrant certificate, that describes the terms of the particular series of warrants we are offering. The following summaries of material provisions of the warrants and the warrant agreements are subject to, and qualified in their entirety by reference to, all the provisions of the warrant agreement and warrant certificate applicable to the particular series of warrants that we may offer under this prospectus. We urge you to read the applicable prospectus supplements related to the particular series of warrants that we may offer under this prospectus, as well as any related free writing prospectuses, and the complete warrant agreements and warrant certificates that contain the terms of the warrants.

**General** 

We will describe in the applicable prospectus supplement the terms relating to a series of warrants being offered, including:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the title of such securities;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the offering price or prices and aggregate number of warrants offered;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the currency or currencies for which the warrants may be purchased;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• if applicable, the designation and terms of the securities with which the warrants are issued and the number of
warrants issued with each such security or each principal amount of such security;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• if applicable, the date on and after which the warrants and the related securities will be separately
transferable;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• if applicable, the minimum or maximum amount of such warrants which may be exercised at any one time;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• in the case of warrants to purchase debt securities, the principal amount of debt securities purchasable upon
exercise of one warrant and the price at which, and currency in which, this principal amount of debt securities may be purchased upon such exercise;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• in the case of warrants to purchase common stock or preferred stock, the number of shares of common stock or
preferred stock, as the case may be, purchasable upon the exercise of one warrant and the price at which, and the currency in which, these shares may be purchased upon such exercise;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the effect of any merger, consolidation, sale or other disposition of our business on the warrant agreements and
the warrants;

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the terms of any rights to redeem or call the warrants;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the terms of any rights to force the exercise of the warrants;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• any provisions for changes to or adjustments in the exercise price or number of securities issuable upon exercise
of the warrants;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the dates on which the right to exercise the warrants will commence and expire;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the manner in which the warrant agreements and warrants may be modified;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• a discussion of any material or special U.S. federal income tax consequences of holding or exercising the
warrants;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the terms of the securities issuable upon exercise of the warrants; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• any other specific terms, preferences, rights or limitations of or restrictions on the warrants.

Before exercising their warrants, holders of warrants will not have any of the rights of holders of the securities purchasable upon such exercise, including:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• in the case of warrants to purchase debt securities, the right to receive payments of principal of, or premium,
if any, or interest on, the debt securities purchasable upon exercise or to enforce covenants in the applicable indenture; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• in the case of warrants to purchase common stock or preferred stock, the right to receive dividends, if any, or
payments upon our liquidation, dissolution or winding up or to exercise voting rights, if any.

**Exercise of Warrants** 

Each warrant will entitle the holder to purchase the securities that we specify in the applicable prospectus supplement at the exercise price that we describe in the applicable prospectus supplement. Unless we otherwise specify in the applicable prospectus supplement, holders of the warrants may exercise the warrants at any time up to the specified time on the expiration date that we set forth in the applicable prospectus supplement. After the close of business on the expiration date, unexercised warrants will become void.

Unless we otherwise specify in the applicable prospectus supplement, holders of the warrants may exercise the warrants by delivering the warrant certificate representing the warrants to be exercised together with specified information, and paying the required amount to the warrant agent in immediately available funds, as provided in the applicable prospectus supplement. We will set forth on the reverse side of the warrant certificate and in the applicable prospectus supplement the information that the holder of the warrant will be required to deliver to the warrant agent in connection with the exercise of the warrant.

Upon receipt of the required payment and the warrant certificate properly completed and duly executed at the corporate trust office of the warrant agent or any other office indicated in the applicable prospectus supplement, we will issue and deliver the securities purchasable upon such exercise. If fewer than all of the warrants represented by the warrant certificate are exercised, then we will issue a new warrant certificate for the remaining amount of warrants. If we so indicate in the applicable prospectus supplement, holders of the warrants may surrender securities as all or part of the exercise price for warrants.

**Governing Law** 

Unless we provide otherwise in the applicable prospectus supplement, the warrants and warrant agreements, and any claim, controversy or dispute arising under or related to the warrants or warrant agreements, will be governed by and construed in accordance with the laws of the State of New York.

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**Enforceability of Rights by Holders of Warrants** 

Each warrant agent will act solely as our agent under the applicable warrant agreement and will not assume any obligation or relationship of agency or trust with any holder of any warrant. A single bank or trust company may act as warrant agent for more than one issue of warrants. A warrant agent will have no duty or responsibility in case of any default by us under the applicable warrant agreement or warrant, including any duty or responsibility to initiate any proceedings at law or otherwise, or to make any demand upon us. Any holder of a warrant may, without the consent of the related warrant agent or the holder of any other warrant, enforce by appropriate legal action its right to exercise, and receive the securities purchasable upon exercise of, its warrants.

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**LEGAL OWNERSHIP OF SECURITIES** 

We can issue securities in registered form or in the form of one or more global securities. We describe global securities in greater detail below. We refer to those persons who have securities registered in their own names on the books that we or any applicable trustee or depositary maintain for this purpose as the "holders" of those securities. These persons are the legal holders of the securities. We refer to those persons who, indirectly through others, own beneficial interests in securities that are not registered in their own names as "indirect holders" of those securities. As we discuss below, indirect holders are not legal holders and investors in securities issued in book-entry form or in street name will be indirect holders.

**Book-Entry Holders** 

We may issue securities in book-entry form only, as we will specify in the applicable prospectus supplement. This means securities may be represented by one or more global securities registered in the name of a financial institution that holds them as depositary on behalf of other financial institutions that participate in the depositary's book-entry system. These participating institutions, which are referred to as participants, in turn, hold beneficial interests in the securities on behalf of themselves or their customers.

Only the person in whose name a security is registered is recognized as the holder of that security. Global securities will be registered in the name of the depositary or its participants. Consequently, for global securities, we will recognize only the depositary as the holder of the securities, and we will make all payments on the securities to the depositary. The depositary passes along the payments it receives to its participants, which in turn pass the payments along to their customers who are the beneficial owners. The depositary and its participants do so under agreements they have made with one another or with their customers; they are not obligated to do so under the terms of the securities.

As a result, investors in a global security will not own securities directly. Instead, they will own beneficial interests in a global security, through a bank, broker or other financial institution that participates in the depositary's book-entry system or holds an interest through a participant. As long as the securities are issued in global form, investors will be indirect holders, and not legal holders, of the securities.

**Street Name Holders** 

A global security may be terminated in certain situations as described under "—Special Situations When a Global Security Will Be Terminated," or issue securities that are not issued in global form. In these cases, investors may choose to hold their securities in their own names or in "street name." Securities held by an investor in street name would be registered in the name of a bank, broker or other financial institution that the investor chooses, and the investor would hold only a beneficial interest in those securities through an account he or she maintains at that institution.

For securities held in street name, we or any applicable trustee or depositary will recognize only the intermediary banks, brokers and other financial institutions in whose names the securities are registered as the holders of those securities, and we or any such trustee or depositary will make all payments on those securities to them. These institutions pass along the payments they receive to their customers who are the beneficial owners, but only because they agree to do so in their customer agreements or because they are legally required to do so. Investors who hold securities in street name will be indirect holders, not holders, of those securities.

**Legal Holders** 

Our obligations, as well as the obligations of any applicable trustee or third party employed by us or a trustee, run only to the legal holders of the securities. We do not have obligations to investors who hold beneficial interests in global securities, in street name or by any other indirect means. This will be the case whether an investor chooses to be an indirect holder of a security or has no choice because we are issuing the securities only in global form.

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For example, once we make a payment or give a notice to the legal holder, we have no further responsibility for the payment or notice even if that legal holder is required, under agreements with its participants or customers or by law, to pass it along to the indirect holders but does not do so. Similarly, we may want to obtain the approval of the holders to amend an indenture, to relieve us of the consequences of a default or of our obligation to comply with a particular provision of an indenture, or for other purposes. In such an event, we would seek approval only from the legal holders, and not the indirect holders, of the securities. Whether and how the legal holders contact the indirect holders is up to the legal holders.

**Special Considerations for Indirect Holders** 

If you hold securities through a bank, broker or other financial institution, either in book-entry form because the securities are represented by one or more global securities or in street name, you should check with your own institution to find out:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• how it handles securities payments and notices;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• whether it imposes fees or charges;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• how it would handle a request for the holders' consent, if ever required;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• whether and how you can instruct it to send you securities registered in your own name so you can be a holder, if
that is permitted in the future;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• how it would exercise rights under the securities if there were a default or other event triggering the need for
holders to act to protect their interests; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• if the securities are in book-entry form, how the depositary's rules and procedures will affect these
matters.

**Global Securities** 

A global security is a security that represents one or any other number of individual securities held by a depositary. Generally, all securities represented by the same global securities will have the same terms.

Each security issued in book-entry form will be represented by a global security that we issue to, deposit with and register in the name of a financial institution or its nominee that we select. The financial institution that we select for this purpose is called the depositary. Unless we specify otherwise in the applicable prospectus supplement, the DTC will be the depositary for all securities issued in book-entry form.

A global security may not be transferred to or registered in the name of anyone other than the depositary, its nominee or a successor depositary, unless special termination situations arise. We describe those situations below under "—Special Situations When a Global Security Will Be Terminated." As a result of these arrangements, the depositary, or its nominee, will be the sole registered owner and legal holder of all securities represented by a global security, and investors will be permitted to own only beneficial interests in a global security. Beneficial interests must be held by means of an account with a broker, bank or other financial institution that in turn has an account with the depositary or with another institution that does. Thus, an investor whose security is represented by a global security will not be a legal holder of the security, but only an indirect holder of a beneficial interest in the global security.

If the prospectus supplement for a particular security indicates that the security will be issued as a global security, then the security will be represented by a global security at all times unless and until the global security is terminated. If termination occurs, we may issue the securities through another book-entry clearing system or decide that the securities may no longer be held through any book-entry clearing system.

**Special Considerations for Global Securities** 

As an indirect holder, an investor's rights relating to a global security will be governed by the account rules of the investor's financial institution and of the depositary, as well as general laws relating to securities transfers.

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We do not recognize an indirect holder as a holder of securities and instead deal only with the depositary that holds the global security.

If securities are issued only as global securities, an investor should be aware of the following:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• an investor cannot cause the securities to be registered in his or her name, and cannot obtain non-global certificates for his or her interest in the securities, except in the special situations we describe below;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• an investor will be an indirect holder and must look to his or her own bank or broker for payments on the
securities and protection of his or her legal rights relating to the securities, as we describe above;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• an investor may not be able to sell interests in the securities to some insurance companies and to other
institutions that are required by law to own their securities in non-book-entry form;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• an investor may not be able to pledge his or her interest in the global security in circumstances where
certificates representing the securities must be delivered to the lender or other beneficiary of the pledge in order for the pledge to be effective;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the depositary's policies, which may change from time to time, will govern payments, transfers, exchanges
and other matters relating to an investor's interest in the global security;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• we and any applicable trustee have no responsibility for any aspect of the depositary's actions or for its
records of ownership interests in the global security, nor will we or any applicable trustee supervise the depositary in any way;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the depositary may, and we understand that DTC will, require that those who purchase and sell interests in the
global security within its book-entry system use immediately available funds, and your broker or bank may require you to do so as well; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• financial institutions that participate in the depositary's book-entry system, and through which an investor
holds its interest in the global security, may also have their own policies affecting payments, notices and other matters relating to the securities.

There may be more than one financial intermediary in the chain of ownership for an investor. We do not monitor and are not responsible for the actions of any of those intermediaries.

**Special Situations When a Global Security Will Be Terminated** 

In a few special situations described below, a global security will terminate and interests in it will be exchanged for physical certificates representing those interests. After that exchange, the choice of whether to hold securities directly or in street name will be up to the investor. Investors must consult their own banks or brokers to find out how to have their interests in securities transferred to their own names, so that they will be direct holders. We have described the rights of holders and street name investors above.

Unless we provide otherwise in the applicable prospectus supplement, the global security will terminate when the following special situations occur:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• if the depositary notifies us that it is unwilling, unable or no longer qualified to continue as depositary for
that global security and we do not appoint another institution to act as depositary within 90 days;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• if we notify any applicable trustee that we wish to terminate that global security; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• if an event of default has occurred with regard to securities represented by that global security and has not
been cured or waived.

The applicable prospectus supplement may also list additional situations for terminating a global security that would apply only to the particular series of securities covered by the prospectus supplement. When a global security terminates, the depositary, and neither we nor any applicable trustee, is responsible for deciding the names of the institutions that will be the initial direct holders.

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**PLAN OF DISTRIBUTION** 

We may sell the securities offered by this prospectus from time to time pursuant to underwritten public offerings, negotiated transactions, block trades or a combination of these methods. We may sell the securities offered by this prospectus to or through underwriters or dealers, through agents, or directly to one or more purchasers. We may distribute securities from time to time in one or more transactions:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• at a fixed price or prices, which may be changed;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• at market prices prevailing at the time of sale;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• at prices related to such prevailing market prices; or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• at negotiated prices.

We may also sell equity securities offered by this prospectus in an "at the market offering" as defined in Rule 415(a)(4) under the Securities Act. Such offering may be made into an existing trading market for such securities in transactions at other than a fixed price, either:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• on or through the facilities of the Nasdaq Global Market or any other securities exchange or quotation or trading
service on which such securities may be listed, quoted or traded at the time of sale; and/or

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• to or through a market maker other than on the Nasdaq Global Market or such other securities exchanges or
quotation or trading services.

Such "at the market offerings," if any, may be conducted by underwriters acting as principal or agent.

A prospectus supplement or supplements (and any related free writing prospectus that we may authorize to be provided to you) will describe the terms of the offering of the securities, including, to the extent applicable:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the name or names of any underwriters, dealers or agents, if any;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the purchase price of the securities and the proceeds we will receive from the sale;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• any over-allotment options under which underwriters may purchase additional securities from us;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• any agency fees or underwriting discounts and other items constituting agents' or underwriters'
compensation;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• any public offering price;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• any discounts or concessions allowed or reallowed or paid to dealers; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• any securities exchange or market on which the securities may be listed.

Only underwriters named in a prospectus supplement are underwriters of the securities offered by such prospectus supplement.

If underwriters are used in the sale, they will acquire the securities for their own account and may resell the securities from time to time in one or more transactions at a fixed public offering price or at varying prices determined at the time of sale. The obligations of the underwriters to purchase the securities will be subject to the conditions set forth in the applicable underwriting agreement. We may offer the securities to the public through underwriting syndicates represented by managing underwriters or by underwriters without a syndicate. Subject to certain conditions, the underwriters will be obligated to purchase all of the securities offered by the prospectus supplement. Any public offering price and any discounts or concessions allowed or reallowed or paid to dealers may change from time to time. We may use underwriters with whom we have a material relationship. We will describe in the prospectus supplement, naming the underwriter, the nature of any such relationship.

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We may sell securities directly or through agents we designate from time to time. We will name any agent involved in the offering and sale of securities, and we will describe any commissions and other compensation we will pay the agent in the prospectus supplement. Unless the prospectus supplement states otherwise, our agent will act on a best-efforts basis for the period of its appointment.

We may authorize agents or underwriters to solicit offers by certain types of institutional investors to purchase securities from us at the public offering price set forth in the prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in the future. We will describe the conditions to these contracts and the commissions we must pay for solicitation of these contracts in the prospectus supplement.

We may provide agents and underwriters with indemnification against civil liabilities related to this offering, including liabilities under the Securities Act, or contribution with respect to payments that the agents or underwriters may make with respect to these liabilities. Agents and underwriters may engage in transactions with, or perform services for, us in the ordinary course of business.

Other than common stock, all securities we offer will be new issues of securities with no established trading market. Any underwriters may make a market in these securities, but will not be obligated to do so and may discontinue any market making at any time without notice. We cannot guarantee the liquidity of the trading markets for any securities.

Any underwriter may engage in overallotment, stabilizing transactions, short covering transactions and penalty bids. Overallotment involves sales in excess of the offering size, which create a short position. Stabilizing transactions permit bids to purchase the underlying security so long as the stabilizing bids do not exceed a specified maximum. Short covering transactions involve purchases of the securities in the open market after the distribution is completed to cover short positions. Penalty bids permit the underwriters to reclaim a selling concession from a dealer when the securities originally sold by the dealer are purchased in a stabilizing or covering transaction to cover short positions. Those activities may cause the price of the securities to be higher than it would otherwise be. If commenced, the underwriters may discontinue any of the activities at any time. These transactions may be effected on any exchange or over-the-counter market or otherwise.

Any agents and underwriters who are qualified market makers on the Nasdaq Global Market may engage in passive market making transactions in the securities on the Nasdaq Global Market in accordance with Rule 103 of Regulation M, during the business day prior to the pricing of the offering, before the commencement of offers or sales of the securities. Passive market makers must comply with applicable volume and price limitations and must be identified as passive market makers. In general, a passive market maker must display its bid at a price not in excess of the highest independent bid for such security; if all independent bids are lowered below the passive market maker's bid, however, the passive market maker's bid must then be lowered when certain purchase limits are exceeded. Passive market making may stabilize the market price of the securities at a level above that which might otherwise prevail in the open market and, if commenced, may be discontinued at any time.

The specific terms of any lock-up provisions with respect to any given offering will be described in the applicable prospectus supplement.

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**LEGAL MATTERS** 

Unless otherwise indicated in the applicable prospectus supplement, certain legal matters in connection with the offering and the validity of the securities offered by this prospectus, and any supplement hereto, will be passed upon by Cooley LLP. Additional legal matters may be passed upon for us or any underwriters, dealers or agents, by counsel that we will name in the applicable prospectus supplement.

**EXPERTS** 

The financial statements of Tectonic Therapeutic, Inc. as of December 31, 2024 and 2023, and for the years then ended, incorporated by reference in this prospectus, have been audited by Deloitte & Touche LLP, an independent registered public accounting firm, as stated in their report. Such financial statements are incorporated by reference in reliance upon the report of such firm, given their authority as experts in accounting and auditing.

**WHERE YOU CAN FIND MORE INFORMATION** 

This prospectus is part of a registration statement we filed with the SEC. This prospectus does not contain all of the information set forth in the registration statement and the exhibits to the registration statement. For further information with respect to us and the securities we are offering under this prospectus, we refer you to the registration statement and the exhibits and schedules filed as a part of the registration statement. Statements in this prospectus or any prospectus supplement about these documents are summaries and each statement is qualified in all respects by reference to the document to which it refers. Neither we nor any agent, underwriter or dealer has authorized any person to provide you with different information. We are not making an offer of these securities in any state where the offer is not permitted. You should not assume that the information in this prospectus is accurate as of any date other than the date on the front page of this prospectus, regardless of the time of delivery of this prospectus or any sale of the securities offered by this prospectus.

We file annual, quarterly and current reports, proxy statements and other information with the SEC. The SEC maintains a website that contains reports, proxy statements and other information regarding issuers that file electronically with the SEC, including us. The address of the SEC website is www.sec.gov.

We maintain a website at www.tectonictx.com. The information contained in, or that can be accessed through, our website is not incorporated by reference herein and is not part of this prospectus.

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**INCORPORATION OF CERTAIN INFORMATION BY REFERENCE** 

The SEC allows us to "incorporate by reference" information that we file with it, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is an important part of this prospectus. Information in this prospectus supersedes information incorporated by reference that we filed with the SEC prior to the date of this prospectus, while information that we file later with the SEC will automatically update and supersede the information in this prospectus. We also incorporate by reference into this prospectus the documents listed below and any future filings made by us with the SEC (other than Current Reports on Form 8-K or portions thereof furnished under Item 2.02 or Item 7.01 and exhibits filed pursuant to Item 9.01 on such form that are related to such items and other portions of documents that are furnished, but not filed, or are otherwise not incorporated into registration statements pursuant to applicable rules promulgated by the SEC) that are filed by us with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act (i) after the date of the filing of the registration statement of which this prospectus is a part and prior to the effectiveness of the registration statement, and (ii) after the effectiveness of the registration statement but prior to the termination of all offerings of securities covered by this prospectus:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• our Annual Report on Form 10-K for the year ended December 31, 2024,
filed with the SEC on [March 20, 2025](http://www.sec.gov/Archives/edgar/data/../../../ix?doc=/Archives/edgar/data/0001681087/000095017025042648/tecx-20241231.htm) and the information specifically incorporated by reference into our
Annual Report on Form 10-K for the year ended December 
31, 2024 from our Definitive Proxy Statement on Schedule 14A, filed with the SEC on [April 25, 2025](http://www.sec.gov/Archives/edgar/data/../../../ix?doc=/Archives/edgar/data/0001681087/000119312525096764/d949345ddef14a.htm) ;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• our Quarterly Report on Form 10-Q for the quarterly period ended
March 31, 2025, filed with the SEC on [May 8, 2025](http://www.sec.gov/Archives/edgar/data/../../../ix?doc=/Archives/edgar/data/0001681087/000095017025067037/tecx-20250331.htm) ;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• our Current Reports on Form 8-K (other than information furnished rather
than filed), filed with the SEC on [January 30, 2025](http://www.sec.gov/Archives/edgar/data/../../../ix?doc=/Archives/edgar/data/0001681087/000119312525016224/d817477d8k.htm) , [February 3, 2025](http://www.sec.gov/Archives/edgar/data/../../../ix?doc=/Archives/edgar/data/0001681087/000119312525018840/d843684d8k.htm) , [May 19, 2025](http://www.sec.gov/Archives/edgar/data/../../../ix?doc=/Archives/edgar/data/0001681087/000119312525122511/d939029d8k.htm) and [June 6, 2025](http://www.sec.gov/Archives/edgar/data/../../../ix?doc=/Archives/edgar/data/0001681087/000119312525137149/d31142d8k.htm) ; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;• the description of our common stock, which is registered under Section 
12 of the Exchange Act, described in [Exhibit 4.1](http://www.sec.gov/Archives/edgar/data/1681087/000095017025042648/tecx-ex4_1.htm) to our Annual Report on Form 10-K for the year ended
December 31, 2024, filed with the SEC on [March 20, 2025](http://www.sec.gov/Archives/edgar/data/../../../ix?doc=/Archives/edgar/data/0001681087/000095017025042648/tecx-20241231.htm) .

We will provide to each person, including any beneficial owner, to whom a prospectus is delivered, without charge upon written or oral request, a copy of any or all of the documents that are incorporated by reference into this prospectus but not delivered with the prospectus, including exhibits which are specifically incorporated by reference into such documents. You should direct any requests for documents by writing or by telephoning us at the following address or phone number:

Tectonic Therapeutic, Inc.

Attention: Chief Financial Officer

490 Arsenal Way, Suite 210

Watertown, Massachusetts 02472

(339) 666-3320

Any statement contained herein or in a document incorporated or deemed to be incorporated by reference into this document will be deemed to be modified or superseded for purposes of the document to the extent that a statement contained in this document or any other subsequently filed document that is deemed to be incorporated by reference into this document modifies or supersedes the statement.

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**Up to $100,000,000**![LOGO](g49849g04g04.jpg)

**Common Stock** 

**PROSPECTUS SUPPLEMENT** 

**TD Cowen** 

**July 15, 2025**