X0609 4 2026-06-05 0 0000751978 VICOR CORP vicr 0000901484 VINCIARELLI PATRIZIO false C/O VICOR CORPORATION 25 FRONTAGE ROAD ANDOVER MA 01810 1 1 1 0 Chairman and CEO 1 Common Stock 167125 I See footnote Common Stock 2026-06-05 4 S 0 1000 266.282 D 8727090 D Common Stock 2026-06-05 4 S 0 800 267.3775 D 8726290 D Common Stock 2026-06-05 4 S 0 900 268.4295 D 8725390 D Common Stock 2026-06-05 4 S 0 800 269.3738 D 8724590 D Common Stock 2026-06-05 4 S 0 1416 270.3738 D 8723174 D Common Stock 2026-06-05 4 S 0 1084 271.443 D 8722090 D Common Stock 2026-06-05 4 S 0 1000 272.8797 D 8721090 D Common Stock 2026-06-05 4 S 0 1457 274.1178 D 8719633 D Common Stock 2026-06-05 4 S 0 1343 275.0588 D 8718290 D Common Stock 2026-06-05 4 S 0 600 276.3973 D 8717690 D Common Stock 2026-06-05 4 S 0 900 277.46 D 8716790 D Common Stock 2026-06-05 4 S 0 1300 278.6729 D 8715490 D Common Stock 2026-06-05 4 S 0 945 280.219 D 8714545 D Common Stock 2026-06-05 4 S 0 2255 281.3249 D 8712290 D Common Stock 2026-06-05 4 S 0 1000 282.4 D 8711290 D Common Stock 2026-06-05 4 S 0 915 283.7548 D 8710375 D Common Stock 2026-06-05 4 S 0 957 284.7206 D 8709418 D Common Stock 2026-06-05 4 S 0 347 285.638 D 8709071 D Common Stock 2026-06-05 4 S 0 892 286.6161 D 8708179 D Common Stock 2026-06-05 4 S 0 83 287.6182 D 8708096 D Common Stock 2026-06-05 4 S 0 6 288.5067 D 8708090 D 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. This sale was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on February 26, 2026. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $265.8900 to $266.7000. The reporting person undertakes to provide to Vicor Corporation, any security holder of Vicor Corporation, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (3) through (23) to this Form 4. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $266.9800 to $267.7200. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $268.0000 to $268.9900. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $269.0100 to $270.0000. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $270.0400 to $271.0300. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $271.0500 to $271.8300. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $272.2500 to $273.2100. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $273.6900 to $274.6700. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $274.7500 to $275.2900. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $276.0000 to $276.8800. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $277.0100 to $278.0000. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $278.1900 to $279.1700. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $279.9700 to $280.9300. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $280.9900 to $281.6800. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $282.0600 to $282.9100. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $283.1600 to $284.0000. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $284.2000 to $285.1600. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $285.2000 to $286.1200. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $286.3800 to $287.3700. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $287.4200 to $288.0000. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $288.5000 to $288.5100. /s/Kemble D. Morrison Attorney in fact for Patrizio Vinciarelli 2026-06-08