# EDGAR Filing Document

**Accession Number:** 0001633979
**File Stem:** 0000950142-23-000413
**Filing Date:** 2023-2
**Character Count:** 14835
**Document Hash:** c10910ab2e833bb328119320f894f3a0
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000950142-23-000413.hdr.sgml**: 20230214

**ACCESSION NUMBER**: 0000950142-23-000413

**CONFORMED SUBMISSION TYPE**: SC 13G/A

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20230214

**DATE AS OF CHANGE**: 20230214

**GROUP MEMBERS**: BRIAN MILLER

**GROUP MEMBERS**: NORTH SOUND MANAGEMENT, INC.

**GROUP MEMBERS**: NORTH SOUND TRADING, LP

**GROUP MEMBERS**: NORTH SOUND VENTURES, LP

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** IsoPlexis Corp
- **CENTRAL INDEX KEY:** 0001615055
- **STANDARD INDUSTRIAL CLASSIFICATION:** LABORATORY ANALYTICAL INSTRUMENTS [3826]
- **IRS NUMBER:** 462179799
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SC 13G/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-92954
- **FILM NUMBER:** 23630347

**BUSINESS ADDRESS:**
- **STREET 1:** 35 NE INDUSTRIAL ROAD
- **CITY:** BRANFORD
- **STATE:** CT
- **ZIP:** 06405
- **BUSINESS PHONE:** 203-208-4111

**MAIL ADDRESS:**
- **STREET 1:** 35 NE INDUSTRIAL ROAD
- **CITY:** BRANFORD
- **STATE:** CT
- **ZIP:** 06405
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** North Sound Trading, LP
- **CENTRAL INDEX KEY:** 0001633979
- **IRS NUMBER:** 465036318
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SC 13G/A

**BUSINESS ADDRESS:**
- **STREET 1:** 115 EAST PUTNAM AVENUE
- **CITY:** GREENWICH
- **STATE:** CT
- **ZIP:** 06830
- **BUSINESS PHONE:** 203-340-8400

**MAIL ADDRESS:**
- **STREET 1:** 115 EAST PUTNAM AVENUE
- **CITY:** GREENWICH
- **STATE:** CT
- **ZIP:** 06830

**UNITED STATES<br> SECURITIES AND EXCHANGE COMMISSION<br> Washington, D.C. 20549**

**SCHEDULE 13G**

**Under the Securities Exchange Act of 1934**

**(Amendment No. 1)\***

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| |
|:---|
| **IsoPlexis Corp.** |
| (Name of Issuer) |
| **Common Stock, no par value** |
| (Title of Class of Securities) |
| **465005106** |
| (CUSIP Number) |
| **December 31, 2022** |
| (Date of Event which Requires Filing of this Statement) |

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Check the appropriate box to designate the rule pursuant to which this Schedule is filed.

☐ Rule 13d-1(b) <br> ☒ Rule 13d-1(c) <br> ☐ Rule 13d-1(d)

\*The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

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| | | |
|:---|:---|:---|
| **CUSIP No. 465005106** | **SCHEDULE 13G** | Page 2 of 9 |

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| | | |
|:---|:---|:---|
| 1 | NAME OF REPORTING PERSON<br>North Sound Trading, LP | |
| 2 | CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP<br>| (a) ☐<br> (b) ☐ |
| 3 | SEC USE ONLY<br>| |
| 4 | CITIZENSHIP OR PLACE OF ORGANIZATION<br>Delaware |  |

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| | |
|:---|:---|
| 5 | SOLE VOTING POWER<br>1,033,000 |
| 6 | SHARED VOTING POWER<br>0 |
| 7 | SOLE DISPOSITIVE POWER<br>1,033,000 |
| 8 | SHARED DISPOSITIVE POWER<br>0 |

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| | | |
|:---|:---|:---|
| | AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON<br>1,033,000 | |
| 10 | CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES<br>| ☐ |
| 11 | PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)<br>2.6% |  |
| 12 | TYPE OF REPORTING PERSON<br>PN |  |

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| | | |
|:---|:---|:---|
| **CUSIP No. 465005106** | **SCHEDULE 13G** | Page 3 of 9 |

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| | | |
|:---|:---|:---|
| 1 | NAME OF REPORTING PERSON<br>North Sound Ventures, LP | |
| 2 | CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP<br>| (a) ☐<br> (b) ☐ |
| 3 | SEC USE ONLY<br>| |
| 4 | CITIZENSHIP OR PLACE OF ORGANIZATION<br>Delaware |  |

---

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| | |
|:---|:---|
| 5 | SOLE VOTING POWER<br>210,987 |
| 6 | SHARED VOTING POWER<br>0 |
| 7 | SOLE DISPOSITIVE POWER<br>210,987 |
| 8 | SHARED DISPOSITIVE POWER<br>0 |

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| | | |
|:---|:---|:---|
| | AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON<br>210,987 | |
| 10 | CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES<br>| ☐ |
| 11 | PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)<br>0.5% |  |
| 12 | TYPE OF REPORTING PERSON<br>PN |  |

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| | | |
|:---|:---|:---|
| **CUSIP No. 465005106** | **SCHEDULE 13G** | Page 4 of 9 |

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| | | |
|:---|:---|:---|
| 1 | NAME OF REPORTING PERSON<br>North Sound Management, Inc. |  |
| 2 | CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP<br>| (a) ☐<br> (b) ☐ |
| 3 | SEC USE ONLY<br>|  |
| 4 | CITIZENSHIP OR PLACE OF ORGANIZATION<br>Delaware |  |

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| | | |
|:---|:---|:---|
| NUMBER OF<br> SHARES<br> BENEFICIALLY OWNED<br> BY EACH REPORTING<br> PERSON<br> WITH | 5 | SOLE VOTING POWER<br>1,243,987 |
| NUMBER OF<br> SHARES<br> BENEFICIALLY OWNED<br> BY EACH REPORTING<br> PERSON<br> WITH | 6 | SHARED VOTING POWER<br>0 |
| NUMBER OF<br> SHARES<br> BENEFICIALLY OWNED<br> BY EACH REPORTING<br> PERSON<br> WITH | 7 | SOLE DISPOSITIVE POWER<br>1,243,987 |
| NUMBER OF<br> SHARES<br> BENEFICIALLY OWNED<br> BY EACH REPORTING<br> PERSON<br> WITH | 8 | SHARED DISPOSITIVE POWER<br>0 |

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| | | |
|:---|:---|:---|
| 9 | AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON<br>1,243,987 |  |
| 10 | CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES<br>| ☐ |
| 11 | PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)<br>3.1% |  |
| 12 | TYPE OF REPORTING PERSON<br>IA, CO |  |

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| | | |
|:---|:---|:---|
| **CUSIP No. 465005106** | **SCHEDULE 13G** | Page 5 of 9 |

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| | | |
|:---|:---|:---|
| 1 | NAME OF REPORTING PERSON<br>Brian Miller |  |
| 2 | CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP<br>| (a) ☐<br> (b) ☐ |
| 3 | SEC USE ONLY<br>|  |
| 4 | CITIZENSHIP OR PLACE OF ORGANIZATION<br>United States of America |  |

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| | | |
|:---|:---|:---|
| NUMBER OF<br> SHARES<br> BENEFICIALLY OWNED<br> BY EACH REPORTING<br> PERSON<br> WITH | 5 | SOLE VOTING POWER<br>3,644,418 |
| NUMBER OF<br> SHARES<br> BENEFICIALLY OWNED<br> BY EACH REPORTING<br> PERSON<br> WITH | 6 | SHARED VOTING POWER<br>0 |
| NUMBER OF<br> SHARES<br> BENEFICIALLY OWNED<br> BY EACH REPORTING<br> PERSON<br> WITH | 7 | SOLE DISPOSITIVE POWER<br>3,644,418 |
| NUMBER OF<br> SHARES<br> BENEFICIALLY OWNED<br> BY EACH REPORTING<br> PERSON<br> WITH | 8 | SHARED DISPOSITIVE POWER<br>0 |

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| | | |
|:---|:---|:---|
| 9 | AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON<br>3,644,418 |  |
| 10 | CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES<br>| ☐ |
| 11 | PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)<br>9.0% |  |
| 12 | TYPE OF REPORTING PERSON<br>IN |  |

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| | | |
|:---|:---|:---|
| **CUSIP No. 465005106** | **SCHEDULE 13G** | Page 6 of 9 |

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| | |
|:---|:---|
| **ITEM 1.**(a) | Name of Issuer: |
|  | IsoPlexis Corp. (the "<u>Issuer</u>") |
| (b) | Address of Issuer's Principal Executive Offices: |
|  | 35 NE Industrial Road<br> Branford, CT 06405 |
| **ITEM 2.** (a) | Name of Person Filing: |
|  | <br> This statement is being filed on behalf of each of the following persons (each, a "<u>Reporting Person</u>" and, collectively, the "Reporting Persons"):<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(1) North Sound Trading, LP<br> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(2) North Sound Ventures, LP<br> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(3) North Sound Management, Inc.<br> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(4) Brian Miller |
| (b) | Address of Principal Business Office, or if none, Residence:<br>The principal business address for each of the Reporting Persons is:<br>c/o North Sound Management, Inc.<br> 115 East Putnam Avenue<br> Greenwich, CT 06830 |
| (c) | Citizenship: |
|  | See row 4 of the cover page of each Reporting Person. |
| (d) | Title of Class of Securities: |
|  | See cover page. |
| (e) | CUSIP Number: |
|  | See cover page. |
| **ITEM 3.** | **IF THIS STATEMENT IS FILED PURSUANT TO** §**240.13D-1(B) OR 240.13D-2(B) OR (C), CHECK WHETHER THE PERSON FILING IS A:** |
|  | Not applicable. |
| **ITEM 4.** | **OWNERSHIP.** |
| (a) | Amount beneficially owned:<br>See row 9 of the cover page of each Reporting Person.<br>As the general partner of North Sound Trading ("NST") and North Sound Ventures ("NSV"), North Sound Management ("NS Management") may be deemed to beneficially own the shares held by NST and NSV. Mr. Miller is the sole owner of NS Management and may be deemed to beneficially own the shares beneficially owned by NS Management. |
| (b) | Percent of class:<br>See row 11 of the cover page of each Reporting Person.<br>The calculations of beneficial ownership percentage is based on 40,351,574 shares of Common Stock issued and outstanding as of February 6, 2023, as reported in the Issuer's Definitive Proxy Statement filed with the Securities and Exchange Commission on February 13, 2023. |

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| | | |
|:---|:---|:---|
| **CUSIP No. 465005106** | **SCHEDULE 13G** | Page 7 of 9 |

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| | | | |
|:---|:---|:---|:---|
|  | (c) | Number of shares as to which such person has: | Number of shares as to which such person has: |
|  |  | (i) | Sole power to vote or to direct the vote:<br>See row 5 of the cover page of each Reporting Person. |
|  |  | (ii) | Shared power to vote or to direct the vote:<br>See row 6 of the cover page of each Reporting Person. |
|  |  | (iii) | Sole power to dispose or to direct the disposition of:<br>See row 7 of the cover page of each Reporting Person. |
|  |  | (iv) | Shared power to dispose or to direct the disposition of:<br>See row 8 of the cover page of each Reporting Person. |
| **ITEM 5.** | **OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS.** | **OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS.** | **OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS.** |
|  | Not applicable. | Not applicable. | Not applicable. |
| **ITEM 6.** | **OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON.** | **OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON.** | **OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON.** |
|  | Not applicable. | Not applicable. | Not applicable. |
| **ITEM 7.** | **IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY.** | **IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY.** | **IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY.** |
|  | Not applicable. | Not applicable. | Not applicable. |
| **ITEM 8.** | **IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP.** | **IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP.** | **IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP.** |
|  | Not applicable. | Not applicable. | Not applicable. |
| **ITEM 9.** | **NOTICE OF DISSOLUTION OF GROUP.** | **NOTICE OF DISSOLUTION OF GROUP.** | **NOTICE OF DISSOLUTION OF GROUP.** |
|  | Not applicable. | Not applicable. | Not applicable. |
| **ITEM 10.** | **CERTIFICATION.** | **CERTIFICATION.** | **CERTIFICATION.** |
|  | By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the Issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under §240.14a-11. | By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the Issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under §240.14a-11. | By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the Issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under §240.14a-11. |

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| | | |
|:---|:---|:---|
| **CUSIP No. 465005106** | **SCHEDULE 13G** | Page 8 of 9 |

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**Exhibit Index**

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| | |
|:---|:---|
| **Exhibit No.** | **Description** |
| 99.1 | [Joint Filing Agreement, dated December 23, 2021, among North Sound Trading LP, North Sound Management, Inc., and Brian Miller (previously filed).](https://www.sec.gov/Archives/edgar/data/1615055/000095014221004162/eh210212171_ex9901.htm) |

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| | | |
|:---|:---|:---|
| **CUSIP No. 465005106** | **SCHEDULE 13G** | Page 9 of 9 |

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**SIGNATURE**

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: February 14, 2023

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| | | |
|:---|:---|:---|
| **NORTH SOUND TRADING, LP** | **NORTH SOUND TRADING, LP** | **NORTH SOUND TRADING, LP** |
| By: North Sound Management, Inc., *its* | By: North Sound Management, Inc., *its* | By: North Sound Management, Inc., *its* |
| *general partner* | *general partner* | *general partner* |
| By: | /s/ Brian Miller | /s/ Brian Miller |
|  | Name: | Brian Miller |
|  | Title: | President |
| **NORTH SOUND VENTURES, LP** | **NORTH SOUND VENTURES, LP** | **NORTH SOUND VENTURES, LP** |
| By: North Sound Management, Inc., *its* | By: North Sound Management, Inc., *its* | By: North Sound Management, Inc., *its* |
| *general partner* | *general partner* | *general partner* |
| By: | /s/ Brian Miller | /s/ Brian Miller |
|  | Name: | Brian Miller |
|  | Title: | President |
| **NORTH SOUND MANAGEMENT, INC.** | **NORTH SOUND MANAGEMENT, INC.** | **NORTH SOUND MANAGEMENT, INC.** |
| By: | /s/ Brian Miller | /s/ Brian Miller |
|  | Name: | Brian Miller |
|  | Title: | President |
| /s/ Brian Miller | /s/ Brian Miller | /s/ Brian Miller |
| Brian Miller | Brian Miller | Brian Miller |

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