SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Schedule 13G

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULES 13d-1 (b), (c) AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO 13d-2 (b)

(Amendment No. 5)*

Conformis, Inc.

(Name of Issuer)

Common Shares, $0.00001 par value per share

(Title of Class of Securities)

20717E101

(CUSIP Number)

March 27, 2019

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

☐ Rule 13d-1(b)

☐ Rule 13d-1(c)

☒ Rule 13d-1(d)

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

Conformis, Inc. (the “Issuer”)

28 Crosby Drive

Bedford, MA 01730

This joint statement on Schedule 13G is filed by aeris CAPITAL Archer L.P. (“Aeris”) and SGR Sagittarius Holding AG (“SGR”), who are collectively referred to herein as the “Reporting Persons.”

The principal business office of Aeris is c/o Avalon Trust & Corporate Services, Ltd., Landmark Sq, 1st Floor, 64 Earth Close, PO Box 715, Grand Cayman, KY1-1107, Cayman Islands. The principal business office of SGR is Brügglistrasse 2, 8852 Altendorf, Switzerland.

Aeris is a Cayman Island limited partnership.

SGR is a corporation organized in Switzerland.

Shares of Common Stock, $0.00001 par value per share (“Common Stock”)

20717E101

As of March 27, 2019, the Reporting Persons in the aggregate beneficially owned 3,281,576 shares of Common Stock of the Issuer, representing approximately 4.8% of such class of securities. The beneficial ownership of each Reporting Person is as follows: (i) Aeris beneficially owns 1,394,639 shares of Common Stock of the Issuer, representing approximately 2.1% of the class, and (ii) SGR beneficially owns 1,886,937 shares of Common Stock of the Issuer, representing approximately 2.8% of the class. The percentages of Common Stock beneficially owned by the Reporting Persons are based on a total of 67,916,658 shares of Common Stock outstanding as of February 28, 2019, as reported in the Issuer’s definitive proxy statement dated March 15, 2019.

If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than 5 percent of the class of securities, check the following.  ☒

Under certain circumstances set forth in the limited partnership agreement of Aeris, the general and limited partners of such entity may be deemed to have the right to receive dividends from, or the proceeds from, the sale of shares of the Issuer owned by each such entity of which they are a partner or member, as the case may be.

Not applicable.

Not applicable.

Not applicable.

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 my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: March 29, 2019