# EDGAR Filing Document

**Accession Number:** 0001846253
**File Stem:** 0001104659-23-001606
**Filing Date:** 2023-1
**Character Count:** 25999
**Document Hash:** 81af61bfd86a8be543385b634bad0a5e
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-23-001606.hdr.sgml**: 20230105

**ACCESSION NUMBER**: 0001104659-23-001606

**CONFORMED SUBMISSION TYPE**: 4

**PUBLIC DOCUMENT COUNT**: 2

**CONFORMED PERIOD OF REPORT**: 20230103

**FILED AS OF DATE**: 20230105

**DATE AS OF CHANGE**: 20230105

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Dean Thompson
- **CENTRAL INDEX KEY:** 0001069096
- **STATE OF INCORPORATION:** DE

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-40720
- **FILM NUMBER:** 23513471

**MAIL ADDRESS:**
- **STREET 1:** 65 EAST 55TH STREET, 18TH FLOOR
- **STREET 2:** C/O AVISTA CAPITAL PARTNERS
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10022

**FORMER NAME:**
- **FORMER CONFORMED NAME:** DEAN THOMPSON
- **DATE OF NAME CHANGE:** 19980827
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Burgstahler David F
- **CENTRAL INDEX KEY:** 0001374179

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-40720
- **FILM NUMBER:** 23513472

**MAIL ADDRESS:**
- **STREET 1:** C/O WARNER CHILCOTT HOLDINGS CO., LTD.
- **STREET 2:** 100 ENTERPRISE DRIVE
- **CITY:** ROCKAWAY
- **STATE:** NJ
- **ZIP:** 07866
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Tamaroff Joshua Alexander
- **CENTRAL INDEX KEY:** 0001705548

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-40720
- **FILM NUMBER:** 23513470

**MAIL ADDRESS:**
- **STREET 1:** C/O AVISTA CAPITAL PARTNERS
- **STREET 2:** 65 EAST 55TH STREET, 18TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10022
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Avista Capital Managing Member V, LLC
- **CENTRAL INDEX KEY:** 0001957307
- **STATE OF INCORPORATION:** DE

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-40720
- **FILM NUMBER:** 23513476

**BUSINESS ADDRESS:**
- **STREET 1:** 65 E. 55TH STREET, 18TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10022
- **BUSINESS PHONE:** 212-593-6900

**MAIL ADDRESS:**
- **STREET 1:** 65 E. 55TH STREET, 18TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10022
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Avista Capital Partners (Offshore) V, L.P.
- **CENTRAL INDEX KEY:** 0001774143
- **STATE OF INCORPORATION:** D0
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-40720
- **FILM NUMBER:** 23513473

**BUSINESS ADDRESS:**
- **STREET 1:** 65 E. 55TH STREET, 18TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10022
- **BUSINESS PHONE:** 212-593-6900

**MAIL ADDRESS:**
- **STREET 1:** 65 E. 55TH STREET, 18TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10022
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Avista Capital Partners V, L.P.
- **CENTRAL INDEX KEY:** 0001774142
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-40720
- **FILM NUMBER:** 23513474

**BUSINESS ADDRESS:**
- **STREET 1:** 65 E. 55TH STREET, 18TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10022
- **BUSINESS PHONE:** 212-593-6900

**MAIL ADDRESS:**
- **STREET 1:** 65 E. 55TH STREET, 18TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10022
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Avista Capital Partners V GP, L.P.
- **CENTRAL INDEX KEY:** 0001957305
- **STATE OF INCORPORATION:** DE

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-40720
- **FILM NUMBER:** 23513475

**BUSINESS ADDRESS:**
- **STREET 1:** 65 E. 55TH STREET, 18TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10022
- **BUSINESS PHONE:** 212-593-6900

**MAIL ADDRESS:**
- **STREET 1:** 65 E. 55TH STREET, 18TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10022
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** OmniAb, Inc.
- **CENTRAL INDEX KEY:** 0001846253
- **STANDARD INDUSTRIAL CLASSIFICATION:** SERVICES-COMMERCIAL PHYSICAL & BIOLOGICAL RESEARCH [8731]
- **IRS NUMBER:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 5980 HORTON STREET
- **STREET 2:** SUITE 600
- **CITY:** EMERYVILLE
- **STATE:** CA
- **ZIP:** 94608
- **BUSINESS PHONE:** 510-250-7800

**MAIL ADDRESS:**
- **STREET 1:** 5980 HORTON STREET
- **STREET 2:** SUITE 600
- **CITY:** EMERYVILLE
- **STATE:** CA
- **ZIP:** 94608

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Avista Public Acquisition Corp. II
- **DATE OF NAME CHANGE:** 20210212

## Exhibit 99.1

**Exhibit 99.1**

<u>Joint Filer Information</u>

---

| | |
|:---|:---|
| Name of Joint Filer: | Avista Capital Managing Member V, LLC |
| Address of Joint Filer: | 65 East 55th Street, 18th Floor |
|  | New York, NY 10022 |
| Relationship of Joint Filer to Issuer: | 10% Owner, Director |
| Issuer Name and Ticker or Trading Symbol: | OmniAb,Inc. [OABI] |
| Date of Earliest Transaction Required to be Reported (Month/Day/Year): | January 3, 2023 |
| Designated Filer: | Avista Capital Managing Member V, LLC |

---

---

| | |
|:---|:---|
| Signature: | Signature: |
| **Avista CAPITAL MANAGING MEMBER V, LLC** | **Avista CAPITAL MANAGING MEMBER V, LLC** |
| /s/ Benjamin Silbert | /s/ Benjamin Silbert |
| Name: | Benjamin Silbert |
| Title: | Attorney-in-fact |

---

Dated: January 5, 2023

<u>Joint Filer Information</u>

(continued)

---

| | |
|:---|:---|
| Name of Joint Filer: | Avista Capital Partners V GP, L.P. |
| Address of Joint Filer: | 65 East 55th Street, 18th Floor |
|  | New York, NY 10022 |
| Relationship of Joint Filer to Issuer: | 10% Owner, Director |
| Issuer Name and Ticker or Trading Symbol: | OmniAb,Inc. [OABI] |
| Date of Earliest Transaction Required to be Reported (Month/Day/Year): | January 3, 2023 |
| Designated Filer: | Avista Capital Managing Member V, LLC |

---

---

| | |
|:---|:---|
| Signature: | Signature: |
| **Avista CAPITAL PARTNERS V GP, L.P.** | **Avista CAPITAL PARTNERS V GP, L.P.** |
| /s/ Benjamin Silbert | /s/ Benjamin Silbert |
| Name: | Benjamin Silbert |
| Title: | Attorney-in-fact |

---

Dated: January 5, 2023

<u>Joint Filer Information</u>

(continued)

---

| | |
|:---|:---|
| Name of Joint Filer: | Avista Capital Partners V, L.P. |
| Address of Joint Filer: | 65 East 55th Street, 18th Floor |
|  | New York, NY 10022 |
| Relationship of Joint Filer to Issuer: | 10% Owner, Director |
| Issuer Name and Ticker or Trading Symbol: | OmniAb,Inc. [OABI] |
| Date of Earliest Transaction Required to be Reported (Month/Day/Year): | January 3, 2023 |
| Designated Filer: | Avista Capital Managing Member V, LLC |

---

---

| | |
|:---|:---|
| Signature: | Signature: |
| **Avista CAPITAL PARTNERS V, L.P.** | **Avista CAPITAL PARTNERS V, L.P.** |
| /s/ Benjamin Silbert | /s/ Benjamin Silbert |
| Name: | Benjamin Silbert |
| Title: | Attorney-in-fact |

---

Dated: January 5, 2023

<u>Joint Filer Information.</u>

(continued)

---

| | |
|:---|:---|
| Name of Joint Filer: | Avista Capital Partners (Offshore) V, L.P. |
| Address of Joint Filer: | 65 East 55th Street, 18th Floor |
|  | New York, NY 10022 |
| Relationship of Joint Filer to Issuer: | 10% Owner, Director |
| Issuer Name and Ticker or Trading Symbol: | OmniAb,Inc. [OABI] |
| Date of Earliest Transaction Required to be Reported (Month/Day/Year): | January 3, 2023 |
| Designated Filer: | Avista Capital Managing Member V, LLC |

---

---

| | |
|:---|:---|
| Signature: | Signature: |
| **Avista CAPITAL PARTNERS (OFFSHORE) V, l.P.** | **Avista CAPITAL PARTNERS (OFFSHORE) V, l.P.** |
| /s/ Benjamin Silbert | /s/ Benjamin Silbert |
| Name: | Benjamin Silbert |
| Title: | Attorney-in-fact |

---

Dated: January 5, 2023

<u>Joint Filer Information</u>

---

| | |
|:---|:---|
| Name of Joint Filer: | Thompson Dean |
| Address of Joint Filer: | 65 East 55th Street, 18th Floor |
|  | New York, NY 10022 |
| Relationship of Joint Filer to Issuer: | 10% Owner, Director |
| Issuer Name and Ticker or Trading Symbol: | OmniAb,Inc. [OABI] |
| Date of Earliest Transaction Required to be Reported (Month/Day/Year): | January 3, 2023 |
| Designated Filer: | Avista Capital Managing Member V, LLC |

---

---

| | |
|:---|:---|
| Signature: | Signature: |
| By: | /s/ Benjamin Silbert |
|  | Name: Benjamin Silbert, Attorney-in-Fact for Thompson Dean |

---

Dated: January 5, 2023

<u>Joint Filer Information</u>

(continued)

---

| | |
|:---|:---|
| Name of Joint Filer: | David Burgstahler |
| Address of Joint Filer: | 65 East 55th Street, 18th Floor |
|  | New York, NY 10022 |
| Relationship of Joint Filer to Issuer: | 10% Owner, Director |
| Issuer Name and Ticker or Trading Symbol: | OmniAb,Inc. [OABI] |
| Date of Earliest Transaction Required to be Reported (Month/Day/Year): | January 3, 2023 |
| Designated Filer: | Avista Capital Managing Member V, LLC |

---

---

| | |
|:---|:---|
| Signature: | Signature: |
| By: | <br> /s/ Benjamin Silbert |
|  | Name: Benjamin Silbert, Attorney-in-Fact for David Burgstahler |

---

Dated: January 5, 2023

<u>Joint Filer Information</u>

(continued)

---

| | |
|:---|:---|
| Name of Joint Filer: | Joshua Tamaroff |
| Address of Joint Filer: | 65 East 55th Street, 18th Floor |
|  | New York, NY 10022 |
| Relationship of Joint Filer to Issuer: | 10% Owner, Director |
| Issuer Name and Ticker or Trading Symbol: | OmniAb,Inc. [OABI] |
| Date of Earliest Transaction Required to be Reported (Month/Day/Year): | January 3, 2023 |
| Designated Filer: | Avista Capital Managing Member V, LLC |

---

---

| | |
|:---|:---|
| Signature: | Signature: |
| By: | /s/ Benjamin Silbert |
|  | Name: Benjamin Silbert, Attorney-in-Fact for Joshua Tamaroff |

---

Dated: January 5, 2023

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## FORM 4

### STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

[ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

[ ] Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Avista Capital Managing Member V, LLC<br><sub>(Last) (First) (Middle)</sub><br>65 EAST 55TH STREET<br>18TH FLOOR<br><sub>(Street)</sub><br>NEW YORK, NY 10022<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2023-01-03 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[X] Director [X] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>OmniAb, Inc. [ OABI ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Avista Capital Partners V GP, L.P.<br><sub>(Last) (First) (Middle)</sub><br>65 EAST 55TH STREET<br>18TH FLOOR<br><sub>(Street)</sub><br>NEW YORK, NY 10022<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2023-01-03 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[X] Director [X] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>OmniAb, Inc. [ OABI ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Avista Capital Partners V, L.P.<br><sub>(Last) (First) (Middle)</sub><br>65 EAST 55TH STREET<br>18TH FLOOR<br><sub>(Street)</sub><br>NEW YORK, NY 10022<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2023-01-03 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[X] Director [X] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>OmniAb, Inc. [ OABI ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Avista Capital Partners (Offshore) V, L.P.<br><sub>(Last) (First) (Middle)</sub><br>65 EAST 55TH STREET<br>18TH FLOOR<br><sub>(Street)</sub><br>NEW YORK, NY 10022<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2023-01-03 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[X] Director [X] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>OmniAb, Inc. [ OABI ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Burgstahler David F<br><sub>(Last) (First) (Middle)</sub><br>65 EAST 55TH STREET<br>18TH FLOOR<br><sub>(Street)</sub><br>NEW YORK, NY 10022<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2023-01-03 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[X] Director [X] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>OmniAb, Inc. [ OABI ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Dean Thompson<br><sub>(Last) (First) (Middle)</sub><br>65 EAST 55TH STREET<br>18TH FLOOR<br><sub>(Street)</sub><br>NEW YORK, NY 10022<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2023-01-03 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[X] Director [X] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>OmniAb, Inc. [ OABI ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Tamaroff Joshua Alexander<br><sub>(Last) (First) (Middle)</sub><br>65 EAST 55TH STREET<br>18TH FLOOR<br><sub>(Street)</sub><br>NEW YORK, NY 10022<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2023-01-03 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[X] Director [X] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>OmniAb, Inc. [ OABI ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | 3. Transaction Code (V) | 3. Transaction Code (V) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | Code | V | Amount | (A) or (D) | Price | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| Common stock, par value $0.0001 per share | 2023-01-03 |  | A<sup>(5)</sup> |  | 53308<sup>(5)</sup> | A | $0 | 15871242<sup>(3)(4)</sup> | I | See Notes<sup>(1)(2)(6)</sup> |

---

## Table II - Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | 4. Transaction Code (V) | 4. Transaction Code (V) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 6. Date Exercisable and Expiration Date | 6. Date Exercisable and Expiration Date | 7. Title and Amount of Underlying Securities | 7. Title and Amount of Underlying Securities | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | Code | V | (A) | (D) | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| Warrants | $11.5 |  |  |  |  |  |  | <sup>(7)(8)</sup> | 2027-11-01 | Common stock, par value $0.0001 | 11345489 |  | 11345489 | I | See Notes<sup>(1)(2)</sup> |
| Stock Options | $3.35 |  |  |  |  |  |  | <sup>(9)</sup> | 2032-12-01 | Common stock, par value $0.0001 | 200000<sup>(9)</sup> |  | 200000<sup>(9)</sup> | I | See Notes<sup>(1)(6)(9)</sup> |

---

### Footnotes:

(1) This form is being filed by each of the following Reporting Persons: (i) Avista Capital Partners V, L.P., a Delaware limited partnership ("ACP V Onshore"), (ii) Avista Capital Partners (Offshore) V, L.P., a Bermuda limited partnership ("ACP V Offshore"), (iii) Avista Capital Partners V GP, L.P., a Delaware limited partnership ("ACP V GP"), which is the general partner of ACP V Onshore and ACP V Offshore, (iv) Avista Capital Managing Member V, LLC, a Delaware limited liability company ("Avista Managing Member"), which is the general partner of ACP V VP, (v) each of Thompson Dean and David Burgstahler, who are the managers of Avista Managing Member (together with ACP V GP and Avista Managing Member, the "Avista Affiliates"), and (vi) Joshua Tamaroff, who is a director of OmniAb, Inc. (f/k/a Avista Public Acquisition Corp. II) (the "Issuer").

(2) ACP V Onshore directly holds 7,283,484 shares of common stock and 5,224,114 warrants. ACP V Offshore directly holds 8,534,450 shares of common stock and 6,121,375 warrants. Each of the Avista Affiliates may be deemed to beneficially own the securities reported on this line item to the extent of their respective pecuniary interests. Each of the Avista Affiliates disclaims beneficial ownership of the securities reported on this line item, except to the extent of their pecuniary interest therein, if any.

(3) In accordance with the letter agreement, dated March 23, 2022, by and among the Issuer, Avista Acquisition LP II, a Cayman Islands limited partnership ("Avista Sponsor"), and other parties (the "Letter Agreement"), if the Triggering Event (as defined in the Letter Agreement) has not occurred during the Earnout Period (as defined in the Letter Agreement), 1,293,299 shares of common stock will be automatically forfeited to the Issuer for no consideration. As a result of the liquidation and distribution of all of the assets of the Avista Sponsor to its limited partners, ACP V Onshore and ACP V Offshore (the "Avista Sponsor Liquidating Distribution"),

(4) and pursuant to a Joinder to the Letter Agreement entered into on December 9, 2022 between ACP V Onshore, ACP V Offshore, Avista Sponsor and the Issuer, ACP V Onshore directly holds 595,508 of the shares of common stock subject to forfeiture pursuant to the terms of the Letter Agreement, and ACP V Offshore holds 697,791 of the shares of common stock subject to forfeiture pursuant to the terms of the Letter Agreement. Additionally, in connection with the Avista Sponsor Liquidating Distribution, each of ACP V Onshore and ACP V Offshore provided to the Issuer an agreement stating that they will each be bound by the transfer restrictions included in the Amended and Restated Registration and Stockholder Rights Agreement, dated as of November 1, 2022, among the Issuer, the Sponsor and the other signatories thereto (the "A&R RSRA") for the duration of the Founder Shares Lock Up Period (as defined in the A&R RSRA).

(5) Represents restricted stock units ("RSUs") granted to Mr. Tamaroff in his capacity as a director of the Issuer, which RSUs vest as to the shares underlying the award in three substantially similar annual installments beginning on November 1, 2023, subject to Mr. Tamaroff's continuing service as a director of the Issuer through the applicable vesting date; provided, that the RSUs shall vest in full (i) in the event of a Change of Control (as defined in the Issuer's 2022 Incentive Award Plan), to the extent Mr. Tamaroff is serving as a director at the time of such transaction, or (ii) in the event that Mr. Tamaroff ceases to serve as a director by reason of death or Permanent Disability (as defined in the Issuer's 2022 Incentive Award Plan).

(6) Mr. Tamaroff is a partner at an affiliate of the Avista Affiliates and has assigned all rights, title and interest in any securities of the Issuer to an affiliate of the Avista Affiliates controlled by Mr. Dean and Mr. Burgstahler. The Avista Affiliates, ACP V Onshore and ACP V Offshore are each "directors by deputization" for the purposes of Section 16 of the Securities Exchange Act of 1934, as amended. Each of the Avista Affiliates and Mr. Tamaroff may be deemed to beneficially own the securities reported on this line item to the extent of their respective pecuniary interests. Each of the Avista Affiliates, ACP V Onshore and ACP V Offshore and Mr. Tamaroff disclaims beneficial ownership of the securities issued to Mr. Tamaroff, except to the extent of their pecuniary interest therein, if any.

(7) In connection with the completion of the Issuer's August 2021 initial public offering, Avista Sponsor purchased 8,233,333 warrants in a private placement from the Issuer, each exercisable to purchase (subject, initially, to the satisfaction of certain material conditions) one share of common stock for $11.50 per share. The material conditions to exercise were satisfied upon the closing of the transactions contemplated by the Agreement and Plan of Merger, dated March 23, 2022, by and among the Issuer, Avista Sponsor and other parties (the "Closing"), and the warrants by their terms became exercisable (including by cash settlement) on December 1, 2022.

(8) In connection with the Amended and Restated Forward Purchase Agreement, dated March 23, 2022, by and among the Issuer, Avista Sponsor and other parties (the "A&R Forward Purchase Agreement"), Avista Sponsor purchased an aggregate 3,112,156 warrants in private placements from the Issuer, each exercisable to purchase (subject, initially, to the satisfaction of certain material conditions) one share of common stock for $11.50 per share. The material conditions to exercise were satisfied on the Closing, and the warrants by their terms became exercisable (including by cash settlement) December 31, 2022.

(9) Represents stock options granted to Mr. Tamaroff in his capacity as a director of the Issuer, which stock options vest in three substantially similar annual installments beginning on November 1, 2023. The Form 4s filed by the Reporting Persons on December 5, 2022 and December 13, 2022 incorrectly reported that 161,849 stock options and 161,849 shares of common stock underlying such stock options were issued to Mr. Tamaroff.

**Remarks:**
Exhibit 99.1 (Joint Filer Information and Signatures) is hereby incorporated by reference herein.

**Signature:** See Exhibit 99.1  
**Date:** 2023-01-05

### Remarks:

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