X0609 4 2026-06-01 0000729580 BEL FUSE INC /NJ BELFB 0001955919 Kozlovsky Suzanne false C/O BEL FUSE INC. 300 EXECUTIVE DRIVE, SUITE 300 WEST ORANGE NJ 07052 1 Global Head of People 0 Class A Common Stock 492 I by 401(k) plan Class B Common Stock 2026-06-01 4 S 0 33 266.98 D 12250 D Class B Common Stock 2026-06-01 4 S 0 92 269.68 D 12158 D Class B Common Stock 2026-06-01 4 S 0 310 270.51 D 11848 D Class B Common Stock 2026-06-01 4 S 0 46 271.56 D 11802 D Class B Common Stock 2026-06-01 4 S 0 214 272.42 D 11588 D Class B Common Stock 2026-06-01 4 S 0 36 274.91 D 11552 D The number of shares held in the 401(k) plan is estimated. This price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $268.95 to $269.95, inclusive. The reporting person undertakes to provide to Bel Fuse Inc. (the "Company"), any security holder of the Company, 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 range set forth in footnote (2) to this Form 4. This price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $270.01 to $270.89, inclusive. The reporting person undertakes to provide to Bel Fuse Inc. (the "Company"), any security holder of the Company, 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 range set forth in footnote (3) to this Form 4. This price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $271.09 to $271.72, inclusive. The reporting person undertakes to provide to Bel Fuse Inc. (the "Company"), any security holder of the Company, 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 range set forth in footnote (4) to this Form 4. This price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $272.335 to $272.78, inclusive. The reporting person undertakes to provide to Bel Fuse Inc. (the "Company"), any security holder of the Company, 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 range set forth in footnote (5) to this Form 4. /s/ Lynn Hutkin, as attorney-in-fact for Suzanne Kozlovsky 2026-06-03