X0306 4/A 2019-02-24 2019-02-26 0 0001408278 Synacor, Inc. SYNC 0001333020 Davi Steven M C/O SYNACOR, INC. 40 LA RIVIERE DRIVE, SUITE 300 BUFFALO NY 14202 0 1 0 0 EVP Technology Common Stock 2019-02-24 4 A 0 25000 0.00 A 43293 D The time-based vesting requirement of these stock units (each stock unit representing a contingent right to receive one share of Issuer common stock) shall be satisfied in six equal semi-annual installments beginning August 24, 2019, subject to the Reporting Person's continuous service through such dates. Stock units for which the time-based vesting requirement has been satisfied will be settled on the first Permissible Trading Day (as defined in the Reporting Person's stock unit agreement) that occurs on or after the day when such stock units vest. This amendment to the Form 4 filed by the Reporting Person on February 26, 2019 is being filed to move the acquired stock units from Table 2 to Table 1. /s/ Timothy J. Heasley, attorney-in-fact 2019-08-09