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                               June 10, 2021

       Sean Mackay
       Chief Executive Officer
       IsoPlexis Corporation
       35 NE Industrial Rd.
       Branford, CT 06405

                                                        Re: IsoPlexis
Corporation
                                                            Draft Registration
Statement on Form S-1
                                                            Submitted May 13,
2021
                                                            CIK No. 0001615055

       Dear Mr. Mackay:

              We have reviewed your draft registration statement and have the
following comments. In
       some of our comments, we may ask you to provide us with information so
we may better
       understand your disclosure.

              Please respond to this letter by providing the requested
information and either submitting
       an amended draft registration statement or publicly filing your
registration statement on
       EDGAR. If you do not believe our comments apply to your facts and
circumstances or do not
       believe an amendment is appropriate, please tell us why in your
response.

             After reviewing the information you provide in response to these
comments and your
       amended draft registration statement or filed registration statement, we
may have additional
       comments.

       Draft Registration Statement on Form S-1 submitted May 13, 2021

       Market, Industry and Other Data, page ii

   1.                                                   Your statements that:
(i) the estimated market and industry data included in the prospectus
                                                        is inherently uncertain
and imprecise, (ii) investors are cautioned not to place undue
                                                        reliance on such market
and industry data or any other such estimates, and (iii) you have
                                                        not independently
verified any third-party information and data from your internal
                                                        research has not been
verified by any independent source may imply an inappropriate
                                                        disclaimer of
responsibility with respect to the third party information. Please either
delete
                                                        these statements or
specifically state that you are liable for such information.
 Sean Mackay
FirstName  LastNameSean Mackay
IsoPlexis Corporation
Comapany
June       NameIsoPlexis Corporation
     10, 2021
June 10,
Page 2 2021 Page 2
FirstName LastName
Prospectus Summary
Overview, page 1

2.       Please define proteomics and bulk proteomics at first use.
3.       We note your statement that your platform has been    rapidly adopted
  by certain parties.
         Your Summary should provide a balanced presentation of your business.
Please provide a
         discussion of the challenges you face in scaling your operations,
including your
         dependence on converting customers to your platform and that growth
may require you to
         incorporate new equipment and implement new technology systems and
laboratory
         processes, as referenced on page 13. Please also disclose in the
Summary that your
         platform is marketed to customers as research-use-only (RUO) products,
as referenced on
         page 27.
Our Platform, page 2

4.       Please revise to provide the basis for your statements that your
IsoSpeak software is
         capable of rapidly returning "publication quality" content.
Recent Developments, page 5

5.       Please revise your disclosure to identify the Sellers that are party
to the Patent Purchase
         Agreement, describe the nature and scope of the intellectual property
acquired and
         disclose the material rights and obligations of the parties under the
agreement. Please
         also file the Patent Purchase Agreement and the Assumption Agreement
as exhibits to the
         registration statement or tell us why such filing is not required.
Risk Factors
Risks Related to Our Intellectual Property
Certain of our in-licensed patents are, and our future owned and in-licensed
patents may be,
subject to a reservation of rights..., page 40

6.       Please provide additional disclosure regarding the technology or
technologies subject
         to march-in rights; the portion of your business that would be
affected by the exercise
         of march-in rights; and whether and how you may be compensated in the
event such rights
         are exercised.
Risks Related to Our Common Stock and This Offering
Our amended and restated bylaws designate a state or federal court located
within the State of
Delaware as the exclusive forum, page 42

7.       Please revise your disclosure to indicate that your forum selection
provision that relates to
         certain litigation, including any derivative action, does not apply to
suits brought to
         enforce any duty or liability created by the Securities Act or
Exchange Act or the rules
         and regulations thereunder, as referenced on page 112. Please also
revise your risk
         factor to disclose that there is also a risk that your exclusive forum
provisions may result
 Sean Mackay
FirstName  LastNameSean Mackay
IsoPlexis Corporation
Comapany
June       NameIsoPlexis Corporation
     10, 2021
June 10,
Page 3 2021 Page 3
FirstName LastName
         in increased costs for investors to bring a claim.
Use of Proceeds, page 53

8.       Please revise to identify the principal purposes for which the net
proceeds are intended to
         be used and the approximate amount intended to be used for each such
purpose. To the
         extent that you do not have a current specific plan for the proceeds,
or a significant portion
         thereof, please include a statement to this effect and add related
disclosure under an
         appropriate heading in the risk factor section. Refer to Item 504 of
Regulation S-K.
Management's Discussion and Analysis of Financial Condition and Results of
Operations
Overview, page 59

9.       We note your disclosure that certain of your suppliers of components
and materials are
         single or sole source suppliers. Please revise your disclosure to
identify your sole source
         suppliers and the components and/or materials they supply to you.
Please also disclose the
         material terms of your agreements with such suppliers. Alternatively,
please explain to us
         why such disclosure would not be material to investors. Please also
file your supply
         agreements as exhibits to your registration statement or tell us why
you believe such filing
         is not required.
Grant Income, page 62

10.      We note your disclosure that you are engaged in various Small Business
Innovation
         Research grants with the federal government. Please expand your
disclosure in your
         Business section to disclose the material terms of these grants,
including any conditions
         on funding, obligations under the grants, and the intellectual
property rights of each party.
         Alternatively, please explain to us why such disclosure would not be
material to investors.
Results of Operations, page 63

11.      Please address the following regarding your research and development
expenses:
             Revise to provide a break down of your research and development
expenses by
             product candidate. If you do not track your expenses by product
candidate, disclose
             that fact.
             Revise to provide a breakdown of your research and development
expense by type of
             expense.
             You disclose at the top of page 64 that a portion of the increase
in research and
             development expense was related to a new product released in March
2021. Revise
             to identify the new product and quantify the amount of expense
related to that
             product.
Critical Accounting Policies and Significant Judgements and Estimates
Share-Based Compensation, page 68

12.      Once you have an estimated offering price or range, please explain to
us the reasons for
 Sean Mackay
FirstName  LastNameSean Mackay
IsoPlexis Corporation
Comapany
June       NameIsoPlexis Corporation
     10, 2021
June 10,
Page 4 2021 Page 4
FirstName LastName
         any differences between the recent valuations of your common stock
leading up to the
         initial public offering and the estimated offering price. Please also
explain how you
         considered recent preferred stock issuances in your valuation of
common stock. This
         information will help facilitate our review of your accounting for
equity issuances
         including stock compensation and beneficial conversion features.
Please discuss with the
         staff how to submit your response.
13.      Revise your table on page 69 to reflect all such equity-based awards
through the date of
         the registration statement.
Our Platform, page 74

14.      We note your disclosure on page 63 that revenue consists of sales of
instruments and
         consumables in addition to service revenue. Please expand your
disclosure to describe the
         principal services that you offer to customers.
Rapid data analysis and insights, page 74

15.      We note your statement that accelerated insights from your IsoSpeak
software can
         significantly shorten drug development timelines. Given the
uncertainty with regard to
         drug development, please revise this statement to remove any
implication that use of your
         platform successfully mitigates such uncertainty.
Our Product Development Approach, page 80

16.      We note your disclosure on page 1 that you are expanding your
capabilities to include
         applications for infectious diseases, inflammatory conditions, and
neurological diseases.
         We also note your disclosure on page 4 that you intend to further
develop your product
         roadmap to integrate sequencing and functional proteomic biology from
single cells to
         enable novel applications in discovery biology and on page 3 that your
long term strategy
         is ultimately to add additional applications serving clinical
diagnostics research that will
         allow you to serve additional markets you believe to be worth
approximately $10 billion.
         You also state on page 16 that you intend to launch additional new
products in the next six
         to twelve months. Please expand your disclosure in the Business
section to describe your
         material research and development projects, including those that are
material to the
         implementation of your growth strategy.
Intellectual Property , page 83

17.      We note your disclosure on page 38 that you rely on an in-license from
certain third
         parties with respect to certain patent rights relating to multiplexed
detection and high
         throughput single cell polyomics, certain patent rights relating to
methods and
         compositions for quantifying metabolites and certain patent rights
relating to the detection
         of target molecules. Please disclose the material terms of this
agreement, including the
         nature and scope of the intellectual property transferred, each
parties' rights and
         obligations, the duration of the agreement, the royalty rates or range
and the royalty term,
 Sean Mackay
FirstName  LastNameSean Mackay
IsoPlexis Corporation
Comapany
June       NameIsoPlexis Corporation
     10, 2021
June 10,
Page 5 2021 Page 5
FirstName LastName
         the termination provisions, aggregate amounts paid under the agreement
to date, and the
         aggregate future potential milestone payments. Please also provide
this disclosure for the
         license agreements referenced on page on F-24 and F-25. With respect
to your license
         agreements with Yale University and California Institute of
Technology, please quantify
         the value of preferred stock issued to your counterparty at the time
of issuance. Please also
         file these agreements as exhibits to the registration statement.
Alternatively, please explain
         to us why such filing is not required.
18.      Please revise to briefly discuss that your products contain software
licensed by third-party
         authors under    open source    licenses, as referenced on page 41.
19.      Please revise your intellectual property disclosure to clearly
identify each material patent
         or group of related patents, the type of patent protection granted for
each technology, the
         product(s) or product candidate(s) dependent on each patent, related
expiration and
         jurisdiction, including any foreign jurisdiction, of each pending or
issued patent. Please
         also revise to include your patent disclosure as of a more recent date
and include
         applicable disclosure for those patents acquired pursuant to the
Patent Purchase
         Agreement.
Employment Agreements , page 97

20.      We note your disclosure that Messrs. Strahley and Siesel each executed
an offer letter
         with the Company in November 2019 and May 2020, respectively. Please
file such
         offer letter agreements as exhibits to your registration statement.
Refer to Item 601(b)(10)
         of Regulation S-K.
Principal Stockholders, page 102

21.      Please identify the natural person or persons who directly or
indirectly exercise sole or
         shared voting and/or dispositive power with respect to the common
stock held by your 5%
         stockholders identified in the table on page 102.
Financial Statements
Note 3 - Fair Value Measurements, page F-14
Note 7 - Debt, page F-18

22.      Please provide us with additional information regarding your
accounting for the loan
         commitment asset of $2.2 million related to the future loan
commitment. evise to identify
         the contractual features of the loan comment that led you to conclude
that the commitment
         for the second tranche under the Credit Agreement qualifies as a
freestanding financial
         instrument required to be recorded at fair value. Tell us the
accounting literature upon
         which you relied in assessing these features.
 Sean Mackay
IsoPlexis Corporation
June 10, 2021
Page 6
General

23.   Please provide us with copies of all written communications, as defined
in Rule 405 under
      the Securities Act, that you, or anyone authorized to do so on your
behalf, present to
      potential investors in reliance on Section 5(d) of the Securities Act,
whether or not they
      retain copies of the communications.
       You may contact Jeanne Bennett at 202-551-3606 or Kevin Vaughn at
202-551-3494 if
you have questions regarding comments on the financial statements and related
matters. Please
contact Deanna Virginio at 202-551-4530 or Christine Westbrook at 202-551-5019
with any
other questions.



                                                           Sincerely,
FirstName LastNameSean Mackay
                                                           Division of
Corporation Finance
Comapany NameIsoPlexis Corporation
                                                           Office of Life
Sciences
June 10, 2021 Page 6
cc:       Matthew Jones, Esq.
FirstName LastName