Oberweis Asset Management Inc holds a diversified book of 180 stocks worth $3.4B as of Q1 2026 (disclosed May 15, 2026, a ~45-day 13F lag). This quarter they opened Leonardo DRS Inc and trimmed Lumentum Holdings Inc. Their largest long position is Applied Optoelectronics Inc at 6% of the equity book.
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curl -H "Authorization: Bearer YOUR_API_KEY" \ "https://arkolith.com/api/v1/funds/937886/holdings"
Use Arkolith to show OBERWEIS ASSET MANAGEMENT INC/'s latest holdings, largest changes, and filing provenance.
Top-heavy: diversified book
Share of the disclosed book in its largest positions. A higher top-5 share means a more concentrated, higher-conviction portfolio.
100% mapped to company sectors
Direct operating-company sectors from our SIC-based security master. ETF/fund and unclassified holdings stay visible separately; this is not ETF look-through exposure.
Estimated $ traded · quarter-end prices, no cost basis
Bars show each stock's share of the portfolio. Click a row for its position history.
| # | Security | Value | Shares | % Port | Last move | History |
|---|---|---|---|---|---|---|
| 1 | Applied Optoelectronics Inc. COM | $198.8M | 2.35M | 5.9% | ▲+15% Added · +310K sh | |
| 2 | Lumentum Hldgs, Inc. COM | $187.1M | 266.2K | 5.5% | ▼−5.2% Reduced · −15K sh | |
| 3 | Credo Technology Group COM | $95.9M | 1.02M | 2.8% | ▲+51% Added · +347K sh | |
| 4 | DigitalOcean Holdings, Inc. COM | $79.6M | 927.5K | 2.3% | ▲+19% Added · +149K sh | |
| 5 | SharkNinja, Inc. COM | $63.5M | 600.0K | 1.9% | ▲+14% Added · +74K sh | |
| 6 | Nova Ltd. COM | $59.9M | 138.0K | 1.8% | ▲+22% Added · +25K sh | |
| 7 | Dana Inc. COM | $54.2M | 1.61M | 1.6% | ▲+102% Added · +815K sh | |
| 8 | BrightSpring Health Services COM | $49.4M | 1.16M | 1.5% | ▲+28% Added · +251K sh | |
| 9 | Macom Technology Solutions COM | $47.9M | 215.9K | 1.4% | ▲+21% Added · +37K sh | |
| 10 | Rambus, Inc COM | $45.3M | 526.3K | 1.3% | ▲+14% Added · +64K sh | |
| 11 | Clean Harbors, Inc. COM | $41.4M | 144.4K | 1.2% | ▲+24% Added · +27K sh | |
| 12 | SiTime Corporation COM | $41.2M | 119.3K | 1.2% | ▲+12% Added · +13K sh | |
| 13 | Ultra Clean Holdings COM | $39.8M | 640.5K | 1.2% | ▲+1.9% Added · +12K sh | |
| 14 | Everus Construction Group COM | $38.6M | 326.5K | 1.1% | ▲+26% Added · +67K sh | |
| 15 | Frontdoor, Inc. COM | $38.0M | 718.0K | 1.1% | ▲+18% Added · +107K sh | |
| 16 | Carpenter Technology Corp. COM | $37.2M | 94.4K | 1.1% | ▲+14% Added · +12K sh | |
| 17 | Skywest Inc COM | $36.0M | 392.5K | 1.1% | ▲+2.7% Added · +10K sh | |
| 18 | Lattice Semiconductor Corporat COM | $34.7M | 374.4K | 1.0% | ▲+19% Added · +60K sh | |
| 19 | Globus Medical, Inc.-A COM | $33.8M | 392.2K | 1.0% | ▲+45% Added · +122K sh | |
| 20 | Camtek, Ltd. COM | $33.8M | 222.8K | 1.0% | ▲+1.8% Added · +4K sh | |
| 21 | Arcutis Biotherapeutics, Inc. COM | $32.2M | 1.37M | 1.0% | ▲+69% Added · +558K sh | |
| 22 | Flowserve Corporation COM | $32.0M | 434.7K | 0.9% | ▲+6.0% Added · +25K sh | |
| 23 | Silicon Motion Techn ADR COM | $31.7M | 282.6K | 0.9% | ▲+20% Added · +46K sh | |
| 24 | Life Time Holdings, Inc. COM | $31.3M | 1.16M | 0.9% | ▲+9.6% Added · +101K sh | |
| 25 | Rush Street Interactive, Inc. COM | $31.2M | 1.43M | 0.9% | ▲+1.6% Added · +23K sh | |
| 26 | FirstCash Holdings, Inc COM | $31.1M | 165.7K | 0.9% | ▲+26% Added · +34K sh | |
| 27 | Fastly, Inc. COM | $31.1M | 1.07M | 0.9% | ▲+55% Added · +381K sh | |
| 28 | Tutor Perini Corp. COM | $30.4M | 393.9K | 0.9% | ▲+1.7% Added · +7K sh | |
| 29 | Dutch Bros., Inc. COM | $30.3M | 598.5K | 0.9% | ▲+48% Added · +194K sh | |
| 30 | Solaris Energy Infrastructur COM | $30.1M | 531.9K | 0.9% | ▲+45% Added · +165K sh | |
| 31 | Merit Medical System Inc COM | $29.2M | 424.2K | 0.9% | ▲+58% Added · +155K sh | |
| 32 | Federal Signal Corp. COM | $28.9M | 267.6K | 0.9% | ▲+61% Added · +101K sh | |
| 33 | American Superconductor COM | $28.8M | 849.9K | 0.8% | ▲+1.7% Added · +14K sh | |
| 34 | Mercury Systems, Inc. COM | $28.5M | 391.0K | 0.8% | ▼−5.5% Reduced · −23K sh | |
| 35 | Arcosa, Inc. COM | $28.4M | 267.7K | 0.8% | ▲+21% Added · +46K sh | |
| 36 | Osi Systems, Inc. COM | $28.3M | 106.6K | 0.8% | ▲+5.1% Added · +5K sh | |
| 37 | Core Natural Resources, Inc. COM | $28.3M | 269.8K | 0.8% | ▲+51% Added · +91K sh | |
| 38 | Waystar Holding Corp. COM | $28.1M | 1.17M | 0.8% | ▲+39% Added · +327K sh | |
| 39 | Encompass Health Corporation COM | $28.0M | 289.5K | 0.8% | ▼−19% Reduced · −69K sh | |
| 40 | Veracyte, Inc. COM | $27.1M | 839.8K | 0.8% | ▲+16% Added · +113K sh | |
| 41 | AAR Corp. COM | $26.8M | 245.1K | 0.8% | ▼−10% Reduced · −28K sh | |
| 42 | ICU Medical, Inc. COM | $26.3M | 203.7K | 0.8% | ▲+21% Added · +36K sh | |
| 43 | Littelfuse, Inc. COM | $24.4M | 71.8K | 0.7% | ▲+15% Added · +10K sh | |
| 44 | Primoris Services Corp. COM | $23.8M | 166.1K | 0.7% | ▲+1.7% Added · +3K sh | |
| 45 | Remitly Global, Inc. COM | $22.8M | 1.45M | 0.7% | ▲+45% Added · +452K sh | |
| 46 | Genpact Ltd. COM | $22.6M | 606.8K | 0.7% | ▲+16% Added · +85K sh | |
| 47 | Assurant, Inc. COM | $22.3M | 102.3K | 0.7% | ▲+23% Added · +19K sh | |
| 48 | Blue Bird Corporation COM | $22.1M | 389.2K | 0.7% | ▲+1.7% Added · +7K sh | |
| 49 | Imax Corp. COM | $21.9M | 577.1K | 0.6% | ▼−12% Reduced · −75K sh | |
| 50 | Levi Strauss & Co. COM | $21.6M | 1.17M | 0.6% | ▲+17% Added · +173K sh |
As-of date vs the date the SEC received each filing
| Quarter | As of | Filed | Positions | Value | Form |
|---|---|---|---|---|---|
| Q1 2026 | Mar 31, 2026 | May 15, 2026 | 180 | $3.4B | 13F-HR |
| Q4 2025 | Dec 31, 2025 | Feb 17, 2026 | 179 | $2.7B | 13F-HR |
| Q3 2025 | Sep 30, 2025 | Nov 17, 2025 | 183 | $2.6B | 13F-HR |
| Q2 2025 | Jun 30, 2025 | Aug 14, 2025 | 185 | $2.3B | 13F-HR |
| Q1 2025 | Mar 31, 2025 | May 15, 2025 | 192 | $2.0B | 13F-HR |
| Q4 2024 | Dec 31, 2024 | Feb 14, 2025 | 196 | $2.1B | 13F-HR |
| Q3 2024 | Sep 30, 2024 | Nov 14, 2024 | 206 | $2.0B | 13F-HR |
| Q2 2024 | Jun 30, 2024 | Aug 14, 2024 | 197 | $1.6B | 13F-HR |
| Q1 2024 | Mar 31, 2024 | May 15, 2024 | 196 | $1.4B | 13F-HR |
| Q4 2023 | Dec 31, 2023 | Feb 14, 2024 | 192 | $1.1B | 13F-HR |
| Q3 2023 | Sep 30, 2023 | Nov 14, 2023 | 195 | $941.5M | 13F-HR |
| Q2 2023 | Jun 30, 2023 | Aug 14, 2023 | 187 | $822.8M | 13F-HR |
| Q1 2023 | Mar 31, 2023 | May 15, 2023 | 174 | $644.5M | 13F-HR |
| Q4 2022 | Dec 31, 2022 | Feb 14, 2023 | 168 | $470.4M | 13F-HR |
| Q3 2022 | Sep 30, 2022 | Nov 14, 2022 | 173 | $427.3M | 13F-HR |
| Q2 2022 | Jun 30, 2022 | Aug 15, 2022 | 164 | $395.1M | 13F-HR |
| Q1 2022 | Mar 31, 2022 | May 16, 2022 | 165 | $499.2M | 13F-HR |
| Q4 2021 | Dec 31, 2021 | Feb 14, 2022 | 160 | $548.1M | 13F-HR |
| Q3 2021 | Sep 30, 2021 | Nov 15, 2021 | 162 | $482.9M | 13F-HR |
| Q2 2021 | Jun 30, 2021 | Aug 16, 2021 | 163 | $456.5M | 13F-HR |
| Q1 2021 | Mar 31, 2021 | May 17, 2021 | 170 | $488.9M | 13F-HR |
| Q4 2020 | Dec 31, 2020 | Feb 16, 2021 | 138 | $379.8M | 13F-HR |
| Q3 2020 | Sep 30, 2020 | Nov 16, 2020 | 126 | $297.0M | 13F-HR |
| Q2 2020 | Jun 30, 2020 | Aug 14, 2020 | 123 | $254.7M | 13F-HR |
Holdings from SEC EDGAR 13F-HR filings, updated quarterly ~45 days after quarter-end. Public domain. The book and weighting are long equity only; disclosed put/call options are listed separately and excluded from those totals. Price-derived performance is withheld until the price-source policy and freshness gate are green.