X0609 4 2026-04-01 0 0000751978 VICOR CORP vicr 0001512868 Davies Philip D false 25 FRONTAGE RD. ANDOVER MA 01810 1 1 0 0 Corp. VP - Sales 1 Common Stock 2026-04-01 4 M 0 1461 30.98 A 3381 D Common Stock 2026-04-01 4 M 0 1611 31.05 A 4992 D Common Stock 2026-04-01 4 S 0 472 158.2874 D 4520 D Common Stock 2026-04-01 4 S 0 300 159.35 D 4220 D Common Stock 2026-04-01 4 S 0 100 160.34 D 4120 D Common Stock 2026-04-01 4 S 0 100 162.61 D 4020 D Common Stock 2026-04-01 4 S 0 1073 164.4556 D 2947 D Common Stock 2026-04-01 4 S 0 627 165.6851 D 2320 D Common Stock 2026-04-01 4 S 0 300 166.49 D 2020 D Common Stock 2026-04-01 4 S 0 100 167.75 D 1920 D Non Qualified Stock Option 30.98 2026-04-01 4 M 0 1461 0 D 2024-09-06 2029-09-06 Common Stock 1461 8539 D Non Qualified Stock Option 31.05 2026-04-01 4 M 0 1611 0 D 2024-06-28 2029-06-28 Common Stock 1611 0 D This sale was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on November 21, 2025. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $158.0000 to $158.7900. 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 (2) through (9) 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 $159.2900 to $159.4300. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $160.3400 to $160.3400 The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $162.6100 to $162.6100. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $163.8500 to $164.8100. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $165.2800 to $166.0100. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $166.3100 to $166.6000. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $167.7500 to $167.7500. /s/Kemble D. Morrison Attorney in fact for Philip Davies 2026-04-02