As filed with the Securities and Exchange Commission on October 5, 2016

Registration No. 333-213111

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

AMENDMENT NO. 2

TO

FORM S-1

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

Biocept, Inc.

(Exact name of registrant as specified in its charter)

5810 Nancy Ridge Drive

San Diego, CA 92121

(858) 320-8200

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Michael W. Nall

Chief Executive Officer and President

Biocept, Inc.

5810 Nancy Ridge Drive

San Diego, CA 92121

(858) 320-8200

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Approximate date of commencement of proposed sale to the public: As soon as practicable after the effective date of this registration statement.

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check the following box.  x

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ¨

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ¨

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration number of the earlier effective registration statement for the same offering.  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 under the Securities Exchange Act of 1934. (Check one):

CALCULATION OF REGISTRATION FEE

The Registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment that specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, as amended, or until the registration statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

EXPLANATORY NOTE

This Amendment No. 2 to the Registration Statement on Form S-1 (File No. 333-213111), or the Registration Statement, of Biocept, Inc. is being filed solely for the purpose of filing Exhibits 1.1, 5.1 and 23.2 to the Registration Statement and updating the Exhibit Index accordingly. This Amendment No. 2 does not modify any provision of the prospectus that forms a part of the Registration Statement and accordingly such prospectus has not been included herein.

PART II

INFORMATION NOT REQUIRED IN PROSPECTUS

The following table sets forth the costs and expenses, other than underwriting discounts and commissions, paid or payable by Biocept, Inc., or the Registrant, in connection with the sale and distribution of the securities being registered. All amounts are estimated except the SEC registration fee and the FINRA filing fee.

Section 145 of the Delaware General Corporation Law authorizes a court to award, or a corporation’s board of directors to grant, indemnity to directors and officers in terms sufficiently broad to permit such indemnification under certain circumstances for liabilities, including reimbursement for expenses incurred, arising under the Securities Act of 1933, as amended, or the Securities Act.

The Registrant’s amended certificate of incorporation provides for indemnification of its directors and executive officers to the maximum extent permitted by the Delaware General Corporation Law, and the Registrant’s amended and restated bylaws provide for indemnification of its directors and executive officers to the maximum extent permitted by the Delaware General Corporation Law.

In addition, the Registrant has entered into indemnification agreements with each of its current directors and executive officers. These agreements will require the Registrant to indemnify these individuals to the fullest extent permitted under Delaware law against liabilities that may arise by reason of their service to the Registrant and to advance expenses incurred as a result of any proceeding against them as to which they could be indemnified. The Registrant also intends to enter into indemnification agreements with its future directors and executive officers.

Since January 1, 2011, the Registrant made sales of the unregistered securities discussed below. The offers, sales and issuances of the securities described below were exempt from registration under the Securities Act by virtue of Section 4(a)(2) of the Securities Act and/or, in the case of compensatory issuances, Securities Act Rule 701, and/or, in the case of conversions, Section 3(a)(9) of the Securities Act. No commissions were paid.

Aspire Capital, LLC Transaction

On December 21, 2015, the Registrant issued to Aspire Capital, LLC 55,000 shares of common stock as a commitment fee and sold to Aspire Capital, LLC 208,334 shares of common stock at $4.80 per share for gross proceeds of $1,000,000. Subsequently, the Registrant sold to Aspire Capital, LLC an aggregate of 173,147 shares of common stock for total proceeds of $544,051.

Note and Warrant Financings

In 30 closings from February 2011 to November 2012, the Registrant sold secured convertible promissory notes with an aggregate principal amount of $12,336,247, together with warrants that subsequently became exercisable for 36,262 shares of its common stock at an exercise price of $30.00 per share, to 11 accredited investors, for aggregate gross proceeds of $12,336,247.

In 21 closings from January 2012 to December 2012, the Registrant sold promissory notes with an aggregate principal amount of $5,960,000, together with warrants that subsequently became exercisable for 17,519 shares of the Registrant’s common stock to five accredited investors at an exercise price of $30.00 per share, for aggregate gross proceeds of $5,960,000. These promissory notes were converted into shares of the Registrant’s common stock upon the closing of its initial public offering.

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In 56 closings from December 2012 through January 2014, the Registrant sold promissory notes with an aggregate principal amount of $5,165,000, together with warrants that subsequently became exercisable for 86,073 shares of the Registrant’s common stock at an exercise price of $30.00 per share, to 14 accredited investors, for aggregate gross proceeds of $5,165,000.

Compensatory Issuances

In 2011 the Company issued 12,086 common stock options (at a $13.86 weighted-average exercise price per share) and 7,958 preferred stock restricted stock units (number of common stock equivalents) to service providers.

In 2012 the Registrant issued 110 common stock options (at a $13.86 weighted-average exercise price per share) and 10,923 common stock restricted stock units to service providers.

In 2013, the Registrant issued 100,146 common stock options (at a $15.54 weighted-average exercise price per share) and 33,734 common stock restricted stock units to service providers.

In 2014, the Registrant issued 215,766 common stock options (at a $20.13 weighted-average exercise price per share) and 14,832 common stock restricted stock units to service providers. Upon the completion of the Registrant’s initial public offering in February 2014, a total of 24,383 preferred stock restricted stock units (number of common stock equivalents) vested in accordance with underlying agreements, including the 7,958 preferred stock restricted stock units (number of common stock equivalents) issued in 2011.

In 2015, the Registrant issued 441,308 common stock options (at a $6.00 weighted-average exercise price per share).

In the six months ended June 30, 2016, the Registrant issued 109,941 common stock options (at a $3.63 weighted average exercise price per share) and 75,831 common stock restricted stock units to service providers. Of the 14,832 common stock restricted units issued to service providers in 2014, 4,449 were declared vested by the Registrant’s Board of Directors and settled in the six months ended June 30, 2016.

Inducement Warrants and Issuances

In September 2012, the Registrant issued 66,666 Series A preferred stock warrants, at an exercise price of $0.60 per share, to its landlord in exchange for certain real estate lease accommodations. The Series A preferred stock warrants are exercisable until September 2019 for 529 shares of the Registrant’s common stock at an exercise price of $75.60 per share.

In June 2013, the Registrant issued 7,936 common stock warrants, at an exercise price to be determined in accordance with contract, to a lender (a 5% beneficial holder) in connection with a note conversion. Upon the completion of the Registrant’s initial public offering in February 2014, the exercise price of these common stock warrants was fixed at $30.00 per share. These common stock warrants were exercisable until February 10, 2016, and were not exercised.

In July 2013 through January 2014, the Registrant issued common stock warrants which became exercisable upon the completion of the Registrant’s initial public offering in February 2014 for an aggregate 42,964 shares of the Registrant’s common stock, at an exercise price of $30.00 per share, to five guarantors in connection with their guaranties of its UBS Bank USA revolving line of credit. These common stock warrants were exercisable until February 10, 2016, and were not exercised.

In September 2013, the Registrant issued an indeterminate number of common stock warrants, at an exercise price to be determined in accordance with contract, to its landlord in connection with a lease amendment. Upon the completion of the Registrant’s initial public offering in February 2014, the exercise price of the common stock warrants issued to its landlord was fixed at $30.00 per share for an aggregate 16,753 shares of the Registrant’s common stock, which are exercisable until February 2019.

Upon the completion of the Registrant’s initial public offering in February 2014, warrants for an aggregate 31,666 shares of the Registrant’s common stock were issued to the underwriters of the Registrant’s initial public offering and are exercisable until February 2019 at a price of $37.50 per share.

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In April 2014, the Registrant issued Oxford Finance LLC a warrant to purchase up to 17,655 shares of the Registrant’s common stock, at an exercise price of $14.16 per share. The warrant was issued in connection with a loan and security agreement between the Registrant and Oxford Finance LLC dated April 30, 2014, and is exercisable until April 2024.

Recapitalization

In November 2011, the Registrant effected a recapitalization in which all outstanding shares of, and warrants to purchase and restricted stock units to obtain, the Registrant’s outstanding Series AA preferred stock and Series BB preferred stock were converted into the same number of shares of, warrants to purchase and restricted stock units to obtain, Series A preferred stock. At the same time, the Registrant effected the 1-for-3 reverse split of its common stock.

Conversions and Exercises

In November 2011, the Registrant’s Executive Chairman exercised 3,402 common stock options, paying an aggregate exercise price of $47,183.

In October 2011, a major stockholder converted 2,064,520 shares of Series AA preferred stock into 16,385 shares of common stock.

In March and April 2013, two employees exercised stock options for 30 shares of common stock, paying an aggregate exercise price of $395.

In June 2013, the holders of promissory notes with an aggregate principal balance of approximately $20,231,000 and accrued but unpaid interest of approximately $2,581,000 voluntarily converted such principal and interest into 42,245,834 shares of the Registrant’s Series A preferred stock. Such shares of Series A preferred stock, along with 27,175,213 shares of other previously outstanding Series A preferred stock, were subsequently converted into an aggregate 550,951 shares of the Registrant’s common stock upon completion of the Registrant’s initial public offering in February 2014.

In the fourth quarter of 2013, four employees exercised 1,317 common stock options, paying an aggregate exercise price of $19,710.

In February 2014:

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In February 2015:

(a) Exhibits

See the Exhibit Index attached to this Registration Statement, which is incorporated by reference herein.

(b) Financial Statement Schedules

No financial statement schedules are provided because the information called for is not required or is shown either in the financial statements or the notes thereto.

The undersigned registrant hereby undertakes:

(1) To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

(i) To include any prospectus required by Section 10(a)(3) of the Securities Act of 1933;

(ii) To reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the SEC pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20 percent change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement;

(iii) To include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement.

(2) That, for the purpose of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(3) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

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(4) That, for the purpose of determining liability under the Securities Act of 1933 to any purchaser: each prospectus filed pursuant to Rule 424(b) as part of a registration statement relating to an offering, other than registration statements relying on Rule 430B or other than prospectuses filed in reliance on Rule 430A, shall be deemed to be part of and included in the registration statement as of the date it is first used after effectiveness; provided, however, that no statement made in a registration statement or prospectus that is part of the registration statement or made in a document incorporated or deemed incorporated by reference into the registration statement or prospectus that is part of the registration statement will, as to a purchaser with a time of contract of sale prior to such first use, supersede or modify any statement that was made in the registration statement or prospectus that was part of the registration statement or made in any such document immediately prior to such date of first use.

(5) That, for the purpose of determining liability of the registrant under the Securities Act of 1933 to any purchaser in the initial distribution of the securities:

The undersigned registrant undertakes that in a primary offering of securities of the undersigned registrant pursuant to this registration statement, regardless of the underwriting method used to sell the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned registrant will be a seller to the purchaser and will be considered to offer or sell such securities to such purchaser:

(i) Any preliminary prospectus or prospectus of the undersigned registrant relating to the offering required to be filed pursuant to Rule 424;

(ii) Any free writing prospectus relating to the offering prepared by or on behalf of the undersigned registrant or used or referred to by the undersigned registrant;

(iii) The portion of any other free writing prospectus relating to the offering containing material information about the undersigned registrant or its securities provided by or on behalf of the undersigned registrant; and

(iv) Any other communication that is an offer in the offering made by the undersigned registrant to the purchaser.

The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act of 1933, each filing of the registrant’s annual report pursuant to section 13(a) or section 15(d) of the Securities Exchange Act of 1934 (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to section 15(d) of the Securities Exchange Act of 1934) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Act and will be governed by the final adjudication of such issue.

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SIGNATURES

Pursuant to the requirements of the Securities Act, the Registrant has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in San Diego, California, on the 5^th day of October, 2016.

Pursuant to the requirements of the Securities Act, this Registration Statement has been signed by the following persons in the capacities and on the dates indicated.

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EXHIBIT INDEX