X0306 4 2015-09-10 0 0000751978 VICOR CORP vicr 0000901484 VINCIARELLI PATRIZIO C/O VICOR CORPORATION 25 FRONTAGE ROAD ANDOVER MA 01810 1 1 1 0 Chairman and CEO Common Stock 2015-09-10 4 P 0 624 9.05 A 20291 I See footnote Common Stock 9758893 D Due to an administrative error, the Form 4 filed on February 27, 2015, incorrectly referenced 19,667 shares as Direct Ownership. As a result of such administrative error, the Form 4 filed on February 27 2015, incorrectly included the 19,667 in the total amount of Direct Ownership securities beneficially owned. Such shares are now correctly being reported as Indirect Ownership securities beneficially owned by the Patrizio Vinciarelli Irrevocable Trust U/A Dated 12/21/2012. These shares are held by the Reporting Person as Trustee of the Patrizio Vinciarelli Irrevocable Trust U/A Dated 12/21/2012, established for the benefit of the child of the Reporting Person. /s/Richard J. Nagel Jr., Attorney in Fact for Patrizio Vinciarelli 2015-09-14