Sec Form 4 Filing - NELSEN ROBERT @ Bellerophon Therapeutics, Inc. - 2015-02-12

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 NELSEN ROBERT 2. Issuer Name and Ticker or Trading Symbol Bellerophon Therapeutics, Inc. [ BLPH] 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) 8725 WEST HIGGINS ROAD, SUITE 290 3. Date of Earliest Transaction (MM/DD/YY) 02/12/2015 (Street) CHICAGO, IL60631 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 02/12/2015 D 752,994 D 0 I See footnote ( 1 ) Common Stock 02/12/2015 A 752,994 A 752,994 I See footnote ( 1 ) ( 2 ) ( 3 ) Common Stock 02/19/2015 P 212,666 A $ 12 965,660 I See footnotes ( 2 ) ( 3 )

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

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other NELSEN ROBERT 8725 WEST HIGGINS ROAD, SUITE 290 CHICAGO, IL60631 X X Signatures /s/ Manesh Naidu, as Attorney-in-Fact for Robert T. Nelsen 02/23/2015 Signature of Reporting Person Date

Explanation of Responses:

( 1 )In connection with the Issuer's conversion from a limited liability company to a corporation, on February 12, 2015, pursuant to an Agreement and Plan of Merger among the Issuer, ARCH Venture Fund VI, L.P. ("ARCH"), IRDO Holding Corp., an affiliate of ARCH ("IRDO"), and certain other entities affiliated with certain other of the Issuer's principal stockholders, IRDO merged with and into the Issuer and the shares of Common Stock held by IRDO immediately prior to the merger were cancelled. In exchange therefor, ARCH received, for no additional consideration, a number of shares of Common Stock equal to the number of shares of Common Stock held by IRDO immediately prior to the merger. ( 2 )These shares are owned directly by ARCH. ARCH Venture Partners VI, L.P. (the "GPLP"), as the sole general partner of ARCH, may be deemed to beneficially own certain of the shares held by ARCH. The GPLP disclaims beneficial ownership of all shares held by ARCH in which the GPLP does not have an actual pecuniary interest. ARCH Venture Partners VI, LLC (the "GPLLC"), as the sole general partner of the GPLP, may be deemed to beneficially own certain of the shares held by ARCH. The GPLLC disclaims beneficial ownership of all shares held by ARCH in which it does not have an actual pecuniary interest. ( 3 )The managing directors of the GPLLC, the Reporting Person, Keith Crandell and Clinton Bybee (together, the "Managing Directors"), are deemed to have voting and dispositive power over the shares held by ARCH, and may be deemed to beneficially own certain of the shares held by ARCH. The Managing Directors, including the Reporting Person, disclaim beneficial ownership of all shares held by ARCH in which they do not have an actual 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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