Sec Form 4 Filing - Ho Gregory P. @ IsoPlexis Corp - 2021-10-12

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

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Ho Gregory P. 2. Issuer Name and Ticker or Trading Symbol IsoPlexis Corp [ ISO] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O ISOPLEXIS CORPORATION, 35 NE INDUSTRIAL RD 3. Date of Earliest Transaction (MM/DD/YY) 10/12/2021 (Street) BRANFORD, CT06405 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 10/12/2021 C 894,128 ( 1 ) ( 2 ) A 894,128 I See Note 3 ( 3 ) Common Stock 10/12/2021 C 338,959 ( 1 ) ( 4 ) A 1,233,087 I See Note 3 ( 3 ) Common Stock 10/12/2021 C 630,209 ( 1 ) ( 5 ) A 1,863,296 I See Note 3 ( 3 ) Common Stock 10/12/2021 C 739,033 ( 1 ) ( 6 ) A 2,602,329 I See Note 3 ( 3 ) Common Stock 10/12/2021 C 689,267 ( 1 ) ( 7 ) A 3,291,596 I See Note 3 ( 3 ) Common Stock 10/12/2021 C 435,136 ( 1 ) ( 8 ) A 3,726,732 I See Note 3 ( 3 ) Common Stock 10/12/2021 C 744,083 ( 1 ) ( 9 ) A 744,083 I See Note 10 ( 10 ) Common Stock 10/12/2021 C 459,781 ( 1 ) ( 11 ) A 1,203,864 I See Note 10 ( 10 ) Common Stock 10/12/2021 C 415,337 ( 1 ) ( 12 ) A 1,619,201 I See Note 10 ( 10 ) Common Stock 10/12/2021 C 215,950 ( 1 ) ( 13 ) A 1,835,151 I See Note 10 ( 10 ) Common Stock 10/12/2021 C 435,136 ( 1 ) ( 8 ) A 2,270,287 I See Note 10 ( 10 ) Common Stock 10/12/2021 C 67,642 ( 1 ) ( 14 ) A 67,642 I See Note 15 ( 15 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Series A Redeemable Convertible Preferred Stock ( 1 ) 10/12/2021 C 107,604 ( 1 ) ( 1 ) Common Stock 860,832 ( 1 ) $ 0 0 I See Note 3 ( 3 ) Series A-2 Redeemable Convertible Preferred Stock ( 1 ) 10/12/2021 C 39,726 ( 1 ) ( 1 ) Common Stock 317,808 ( 1 ) $ 0 0 I See Note 3 ( 3 ) Series A-2 Redeemable Convertible Preferred Stock ( 1 ) 10/12/2021 C 87,398 ( 1 ) ( 1 ) Common Stock 699,184 ( 1 ) $ 0 0 I See Note 10 ( 10 ) Series A-2 Redeemable Convertible Preferred Stock ( 1 ) 10/12/2021 C 7,945 ( 1 ) ( 1 ) Common Stock 63,560 ( 1 ) $ 0 0 I See Note 15 ( 15 ) Series B Redeemable Convertible Preferred Stock ( 1 ) 10/12/2021 C 73,571 ( 1 ) ( 1 ) Common Stock 588,568 ( 1 ) $ 0 0 I See Note 3 ( 3 ) Series B Redeemable Convertible Preferred Stock ( 1 ) 10/12/2021 C 53,480 ( 1 ) ( 1 ) Common Stock 427,840 ( 1 ) $ 0 0 I See Note 10 ( 10 ) Series B-2 Redeemable Convertible Preferred Stock ( 1 ) 10/12/2021 C 84,347 ( 1 ) ( 1 ) Common Stock 674,776 ( 1 ) $ 0 0 I See Note 3 ( 3 ) Series B-2 Redeemable Convertible Preferred Stock ( 1 ) 10/12/2021 C 47,403 ( 1 ) ( 1 ) Common Stock 379,224 ( 1 ) $ 0 0 I See Note 10 ( 10 ) Series C Redeemable Convertible Preferred Stock ( 1 ) 10/12/2021 C 78,999 ( 1 ) ( 1 ) Common Stock 631,992 ( 1 ) $ 0 0 I See Note 3 ( 3 ) Series C Redeemable Convertible Preferred Stock ( 1 ) 10/12/2021 C 24,833 ( 1 ) ( 1 ) Common Stock 198,664 ( 1 ) $ 0 0 I See Note 10 ( 10 ) Series C-2 Redeemable Convertible Preferred Stock ( 1 ) 10/12/2021 C 51,522 ( 1 ) ( 1 ) Common Stock 412,176 ( 1 ) $ 0 0 I See Note 3 ( 3 ) Series C-2 Redeemable Convertible Preferred Stock ( 1 ) 10/12/2021 C 51,522 ( 1 ) ( 1 ) Common Stock 412,176 ( 1 ) $ 0 0 I See Note 10 ( 10 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Ho Gregory P. C/O ISOPLEXIS CORPORATION 35 NE INDUSTRIAL RD BRANFORD, CT06405 X X Signatures /s/ Shane Sevier, attorney-in-fact for Gregory P. Ho 10/14/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Shares of Series A Redeemable Convertible Preferred Stock, par value $0.001, of the Issuer, Series A-2 Redeemable Convertible Preferred Stock, par value $0.001, of the Issuer, Series B Redeemable Convertible Preferred Stock, par value $0.001, of the Issuer, Series B-2 Redeemable Convertible Preferred Stock, par value $0.001, of the Issuer, Series C Redeemable Convertible Preferred Stock, par value $0.001, of the Issuer and Series C-2 Redeemable Convertible Preferred Stock, par value $0.001, of the Issuer (collectively, the "Preferred Stock") were convertible on a one-for-eight basis into shares of Common Stock of the Issuer at the option of the holder at any time and automatically converted upon the closing of the Issuer's initial public offering. The Preferred Stock had no expiration date. ( 2 )Includes 33,296 shares of Common Stock issued per dividends accrued to but not including October 12, 2021. ( 3 )The Reporting Person is a managing member of Spring Mountain Capital G.P., LLC, a Delaware limited liability company ("SMC GP"). SMC GP is the managing member of SMC Growth Capital II GP, LLC, a Delaware limited liability company ("GCII GP"). GCII GP is the general partner of SMC Growth Capital Partners II, LP ("GCII"), the direct beneficial owner of the securities. The Reporting Person disclaims beneficial ownership, within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the securities held by GCII in which the Reporting Person has no pecuniary interest. ( 4 )Includes 21,151 shares of Common Stock issued per dividends accrued to but not including October 12, 2021. ( 5 )Includes 41,641 shares of Common Stock issued per dividends accrued to but not including October 12, 2021. ( 6 )Includes 64,257 shares of Common Stock issued per dividends accrued to but not including October 12, 2021. ( 7 )Includes 57,275 shares of Common Stock issued per dividends accrued to but not including October 12 , 2021. ( 8 )Includes 22,960 shares of Common Stock issued per dividends accrued to but not including October 12, 2021. ( 9 )Includes 44,899 shares of Common Stock issued per dividends accrued to but not including October 12, 2021. ( 10 )The Reporting Person is a managing member of SMC GP. SMC GP is the managing member of SMC Private Equity Holdings G.P., LLC, a Delaware limited liability company ("PEH GP"). PEH GP is the general partner of SMC Private Equity Holdings, LP ("PEH"), the direct beneficial owner of the securities. The Reporting Person disclaims beneficial ownership, within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the securities held by PEH in which the Reporting Person has no pecuniary interest. ( 11 )Includes 31,941 shares of Common Stock issued per dividends accrued to but not including October 12, 2021. ( 12 )Includes 36,113 shares of Common Stock issued per dividends accrued to but not including October 12, 2021. ( 13 )Includes 17,286 shares of Common Stock issued per dividends accrued to but not including October 12, 2021. ( 14 )Includes 4,082 shares of Common Stock issued per dividends accrued to but not including October 12, 2021. ( 15 )The Reporting Person is a managing member of SMC Holdings II G.P., LLC, a Delaware limited liability company ("Holdings GP"). Holdings GP is the general partner of SMC Holdings II, LP ("Holdings"), the direct beneficial owner of the securities. The Reporting Person disclaims beneficial ownership, within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the securities held by Holdings in which the Reporting Person has no pecuniary interest.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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