Bel Fuse Inc.

SecurityBELFB / Bel Fuse Inc.
InstitutionBoston Partners
Latest Disclosed Ownership65,443 shares
Latest Disclosed Value $ 12,956,410
Boston Partners reports 4.47% increase in ownership of BELFB / Bel Fuse Inc.

On May 11, 2026 - Boston Partners filed a 13F-HR form disclosing ownership of 65,443 shares of Bel Fuse Inc. (US:BELFB) valued at $12,956,405 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 62,643 shares of Bel Fuse Inc.. This represents a change in shares of 4.47% during the quarter. The current value of the position is $18,329,930 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-11 2026-03-31 13F BEL FUSE CL B 077347300 65,443 2,800 4.47 12,956 21.93 0.0058
2026-02-13 2025-12-31 13F BEL FUSE CL B 077347300 62,643 6,911 12.40 10,626 35.21 0.0110
2025-11-13 2025-09-30 13F BEL FUSE CL B 077347300 55,732 4,425 8.62 7,859 56.80 0.0081
2025-08-12 2025-06-30 13F/A-1 BEL FUSE CL B 077347300 51,307 13,234 34.76 5,012 75.86 0.0056
2025-08-07 2025-06-30 13F BEL FUSE CL B 077347300 51,307 13,234 5,012 0.0023
2025-05-13 2025-03-31 13F BEL FUSE CL B 077347300 38,073 -1,335 -3.39 2,850 -12.28 0.0034
2025-02-11 2024-12-31 13F BEL FUSE CL B 077347300 39,408 -498 -1.25 3,250 3.70 0.0040
2024-11-12 2024-09-30 13F BEL FUSE CL B 077347300 39,906 -3,527 -8.12 3,133 10.59 0.0037
2024-08-14 2024-06-30 13F BEL FUSE CL B 077347300 43,433 -2,309 -5.05 2,834 2.72 0.0035
2024-05-28 2024-03-31 13F/A-1 BEL FUSE CL B 077347300 45,742 -2,078 -4.35 2,759 -13.60 0.0033
2024-05-13 2024-03-31 13F BEL FUSE CL B 077347300 45,742 -2,078 2,759 0.0014
2024-02-07 2023-12-31 13F BEL FUSE CL B 077347300 47,820 -67,085 -58.38 3,193 -41.78 0.0042
2023-11-08 2023-09-30 13F BEL FUSE CL B 077347300 114,905 -17,403 -13.15 5,483 -27.81 0.0076
2023-08-10 2023-06-30 13F BEL FUSE CL B 077347300 132,308 -7,625 -5.45 7,596 44.45 0.0102
2023-05-09 2023-03-31 13F BEL FUSE CL B 077347300 139,933 -7,641 -5.18 5,259 8.23 0.0072
2023-02-08 2022-12-31 13F BEL FUSE CL B 077347300 147,574 -8,818 -5.64 4,858 23.02 0.0066
2022-11-09 2022-09-30 13F BEL FUSE CL B 077347300 156,392 -2,823 -1.77 3,949 59.43 0.0058
2022-08-10 2022-06-30 13F BEL FUSE CL B 077347300 159,215 -3,816 -2.34 2,477 -14.85 0.0035
2022-05-10 2022-03-31 13F BEL FUSE CL B 077347300 163,031 -2,073 -1.26 2,909 36.25 0.0035
2022-02-04 2021-12-31 13F BEL FUSE CL B 077347300 165,104 -1,887 -1.13 2,135 2.89 0.0026
2021-11-05 2021-09-30 13F BEL FUSE CL B 077347300 166,991 4,805 2.96 2,075 -11.13 0.0026
2021-08-12 2021-06-30 13F BEL FUSE CL B 077347300 162,186 2,102 1.31 2,335 -26.66 0.0030
2021-05-10 2021-03-31 13F BEL FUSE CL B 077347300 160,084 96 0.06 3,184 32.39 0.0043
2021-02-10 2020-12-31 13F/A-1 BEL FUSE CL B 077347300 159,988 -1,014 -0.63 2,405 39.83 0.0037
2021-02-04 2020-12-31 13F BEL FUSE CL B 077347300 159,988 -1,014 2,405 1,442.8571
2020-11-13 2020-09-30 13F/A-1 BEL FUSE CL B 077347300 161,002 -13,650 -7.82 1,720 -8.22 0.0031
2020-11-09 2020-09-30 13F BEL FUSE CL B 077347300 174,652 0 1,874 1,375.7392
2020-08-12 2020-06-30 13F BEL FUSE CL B 077347300 174,652 -51,737 -22.85 1,874 -15.01 0.0034
2020-05-13 2020-03-31 13F BEL FUSE CL B 077347300 226,389 -1,681 -0.74 2,205 -52.83 0.0044
2020-02-06 2019-12-31 13F/A-1 BEL FUSE CL B 077347300 228,070 2,091 0.93 4,675 37.66 0.0062
2019-11-20 2019-09-30 13F/A-1 BEL FUSE CL B 077347300 225,979 -2,505 -1.10 3,396 -13.43 0.0046
2019-11-08 2019-09-30 13F BEL FUSE CL B 077347300 228,484 0 3,923 0.0052
2019-08-26 2019-06-30 13F/A-1 BEL FUSE CL B 077347300 228,484 -13,704 -5.66 3,923 -35.93 0.0051
2019-08-09 2019-06-30 13F BEL FUSE CL B 077347300 228,484 -13,704 3,923
2019-05-13 2019-03-31 13F/A-1 BEL FUSE CL B 077347300 242,188 5,984 2.53 6,123 40.73 0.0081
2019-05-03 2019-03-31 13F BEL FUSE CL B 077347300 242,188 5,984 6,123
2019-02-07 2018-12-31 13F BEL FUSE CL B 077347300 236,204 3,379 1.45 4,351 -29.48 0.0063
2018-11-14 2018-09-30 13F BEL FUSE CL B 077347300 232,825 -3,981 -1.68 6,170 24.67 0.0072
2018-08-03 2018-06-30 13F BEL FUSE CL B 077347300 236,806 -37,486 -13.67 4,949 -4.53 0.0059
2018-05-04 2018-03-31 13F BEL FUSE CL B 077347300 274,292 -13,942 -4.84 5,184 -28.56 0.0063
2018-02-14 2017-12-31 13F/A-1 BEL FUSE CL B 077347300 288,234 -7,736 -2.61 7,256 -21.42 0.0085
2018-02-01 2017-12-31 13F BEL FUSE CL B 077347300 288,234 -7,736 7,256
2017-11-02 2017-09-30 13F BEL FUSE CL B 077347300 295,970 -2,991 -1.00 9,234 25.05 0.0114
2017-08-02 2017-06-30 13F BEL FUSE CL B 077347300 298,961 185 0.06 7,384 -3.27 0.0094
2017-05-03 2017-03-31 13F BEL FUSE CL B 077347300 298,776 6,206 2.12 7,634 -15.55 0.0097
2017-02-06 2016-12-31 13F BEL FUSE CL B 077347300 292,570 7,755 2.72 9,040 31.49 0.0119
2016-11-09 2016-09-30 13F BEL FUSE CL B 077347300 284,815 20,066 7.58 6,875 46.06 0.0096
2016-08-05 2016-06-30 13F BEL FUSE CL B 077347300 264,749 5,844 2.26 4,707 24.52 0.0068
2016-05-12 2016-03-31 13F BEL FUSE CL B 077347300 258,905 54,133 26.44 3,780 6.75 0.0056
2016-02-08 2015-12-31 13F BEL FUSE CL B 077347300 204,772 5,037 2.52 3,541 -8.81 0.0051
2015-11-10 2015-09-30 13F BEL FUSE CL B 077347300 199,735 4,194 2.14 3,883 -3.24 0.0059
2015-08-10 2015-06-30 13F BEL FUSE CL B 077347300 195,541 1,330 0.68 4,013 8.58 0.0058
2015-05-05 2015-03-31 13F BEL FUSE CL B 077347300 194,211 -16,505 -7.83 3,696 -35.84 0.0055
2015-02-09 2014-12-31 13F BEL FUSE CL B 077347300 210,716 22,622 12.03 5,761 23.81 0.0086
2014-11-12 2014-09-30 13F BEL FUSE CL B 077347300 188,094 83,750 80.26 4,653 73.68 0.0076
2014-08-08 2014-06-30 13F BEL FUSE CL B 077347300 104,344 0 0.00 2,679 17.24 0.0045
2014-05-07 2014-03-31 13F BEL FUSE CL B 077347300 104,344 875 0.85 2,285 3.63 0.0042
2014-02-06 2013-12-31 13F BEL FUSE CL B 077347300 103,469 -995 -0.95 2,205 21.02 0.0045
2013-11-12 2013-09-30 13F BEL FUSE CL B 077347300 104,464 -1,865 -1.75 1,822 27.41 0.0044
2013-08-01 2013-06-30 13F BEL FUSE CL B 077347300 106,329 106,329 1,430 0.0039
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.