X0609 4 2026-05-29 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 2026-05-29 4 S 0 200 318.665 D 8827890 D Common Stock 2026-05-29 4 S 0 397 321.461 D 8827493 D Common Stock 2026-05-29 4 S 0 1724 322.7226 D 8825769 D Common Stock 2026-05-29 4 S 0 2983 323.5067 D 8822786 D Common Stock 2026-05-29 4 S 0 1261 324.9154 D 8821525 D Common Stock 2026-05-29 4 S 0 3034 325.5904 D 8818491 D Common Stock 2026-05-29 4 S 0 1200 326.6675 D 8817291 D Common Stock 2026-05-29 4 S 0 1000 328.0256 D 8816291 D Common Stock 2026-05-29 4 S 0 1000 329.6646 D 8815291 D Common Stock 2026-05-29 4 S 0 2800 330.692 D 8812491 D Common Stock 2026-05-29 4 S 0 2000 331.7875 D 8810491 D Common Stock 2026-05-29 4 S 0 516 333.6634 D 8809975 D Common Stock 2026-05-29 4 S 0 85 334.4462 D 8809890 D Common Stock 2026-05-29 4 S 0 1000 336.166 D 8808890 D Common Stock 2026-05-29 4 S 0 400 337.045 D 8808490 D Common Stock 2026-05-29 4 S 0 237 340.2152 D 8808253 D Common Stock 2026-05-29 4 S 0 163 341.7466 D 8808090 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 $318.6600 to $318.6700. 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 (19) 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 $321.0700 to $322.0100. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $322.1400 to $323.1100. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $323.1700 to $324.0600. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $324.1900 to $325.1800. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $325.2100 to $326.0600. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $326.2200 to $327.1600. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $327.5600 to $328.5200. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $329.2200 to $330.1700. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $330.2200 to $331.2100. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $331.2200 to $332.0100. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $333.3100 to $333.8300. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $334.3900 to $334.5500. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $335.7000 to $336.3700. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $337.0000 to $337.1100. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $340.0000 to $340.6300. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $341.0000 to $341.9000. /s/Quentin A. Fendelet Attorney in Fact for Patrizio Vinciarelli 2026-06-01