Filing Details

Item 1(a).

Name of Issuer:

Catalyst Biosciences, Inc. (the "Issuer").

Item 1(b).

Address of Issuer's Principal Executive Offices:

260 Littlefield Avenue

South San Francisco, California 94080

Item 2(a).

Name of Persons Filing:

This Statement is filed on behalf of each of the following persons (collectively, the "Reporting Persons"):

Item 2(b).

Address of Principal Business Office or, if None, Residence:

The address of the principal business office of each of the Reporting Persons is 900 Third Avenue, Suite 201.1, New York, New York 10022.

Item 2(c).

Citizenship:

Item 2(d).

Title of Class of Securities:

Common Stock, par value $0.001 per share (the "Common Stock")

Item 2(e).

CUSIP Number:

14888D208

Item 3.

If This Statement is Filed Pursuant to Rule 13d 1(b), or 13d-2(b) or (c), Check Whether the Person Filing is a:

Item 4.

Ownership.

Provide the following information regarding the aggregate number and percentage of the class of securities of the Issuer.

(a)

Amount beneficially owned:

As of the close of business on December 26, 2017, the Reporting Persons may be deemed to have  beneficially owned 311,175 shares of Common Stock.

(b)

Percent of class:

The aggregate percentage of Common Stock reported owned by each person named herein is based upon approximately 5,813,780 shares of Common Stock outstanding as of December 20, 2017, which is the total number of Common Stock outstanding as reported in the Issuer's Prospectus Supplement on Form 424B5 filed with the Securities and Exchange Commission on December 21, 2017. As of the close of business on December 26, 2017, the Reporting Persons may be deemed to have beneficially owned approximately 5.4% of the outstanding Common Stock.

(c)

Number of shares as to which such person has:

(i)

Sole power to vote or to direct the vote:

See Cover Pages Items 5-9.

(ii)

Shared power to vote or to direct the vote

See Cover Pages Items 5-9.

(iii)

Sole power to dispose or to direct the disposition of

See Cover Pages Items 5-9.

(iv)

Shared power to dispose or to direct the disposition of

See Cover Pages Items 5-9.

Item 5.

Ownership of Five Percent or Less of a Class.

If this statement is being filed to report the fact that as of the date hereof the Reporting Persons have ceased to be the beneficial owner of more than five percent of the class of securities, check the following [  ].

Item 6.

Ownership of More than Five Percent on Behalf of Another Person.

Not applicable.

Item 7.

Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company.

Not applicable.

Item 8.

Identification and Classification of Members of the Group.

See Exhibit A.

Item 9.

Notice of Dissolution of Group.

Not applicable.

Item 10.

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.

SIGNATURES

After reasonable inquiry and to the best of its knowledge and belief, each of the undersigned certifies that the information with respect to it set forth in this statement is true, complete, and correct.