UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2018 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: 001-36481 ASPEN AEROGELS, INC. (Exact name of registrant as specified in its charter) Delaware 04-3559972 (State or other jurisdiction o ...

Aspen Aerogels, Inc. (NYSE:ASPN) Q4 2018 Earnings Conference Call February 21, 2019 5:00 PM ET Company Participants John Fairbanks – Chief Financial Officer Don Young – President and Chief Executive Officer Conference Call Participants Eric Stine – Craig-Hallum Chip Moore – Canaccord Sean Hannan – Needham & Company Operator Good afternoon. My name is Rob and I will be your conference operator today. At this time, I would like to welcome everyone to the Aspen Aerogels Fourth Quarter 2018 Earnings Call. All l ...