UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ Quarterly Report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 For the quarterly period ended September 30, 2020 OR ☐ Transition report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 For the transition period from to . Commission File Number: 001-37985 ANAPTYSBIO, INC. (Exact name of registrant as specified in its charter) Delaware 20-3828755 (State or other jurisdiction of in ...