Oberweis Asset Management Inc./
In its 13F for Q1 2026 (holdings as of March 31, 2026, filed May 15, 2026), Oberweis Asset Management Inc./ reported 179 stock positions worth $3.4 billion. Its top holding was Applied Optoelectronics (AAOI) at 5.9% of the portfolio, followed by Lumentum (LITE, 5.5%) and Credo Technology Group Holdi (CRDO, 2.8%). Compared with Q4 2025, it opened 21 new positions, sold out of 20, added to 130 and reduced 19. The biggest buy was Applied Optoelectronics (AAOI, shares +15%) and the biggest sale Ambarella (AMBA, shares −52%).
- Most Recent 13F
- Q2 2026
- Location
- LISLE, IL
- CIK
- 0000937886
- Portfolio Value
- $3.4B (Q1 2026)
- SEC Filing
- 0001213900-26-057307 ↗ filed May 15, 2026
Holdings Value
Holdings 179 stocks · $3.4B
| AAOI Applied Optoelectronics Inc. | 5.87% | 2,349,969 | $198.8M | Add +15.2% |
| LITE Lumentum Holdings Inc. | 5.53% | 266,222 | $187.1M | Reduce -5.2% |
| CRDO Credo Technology Group Holdi | 2.83% | 1,021,968 | $95.9M | Add +51.3% |
| DOCN Digitalocean Holdings Inc. | 2.35% | 927,505 | $79.6M | Add +19.1% |
| SN Sharkninja Inc. | 1.88% | 599,970 | $63.5M | Add +14.0% |
| NVMI Nova Ltd. | 1.77% | 137,955 | $59.9M | Add +21.8% |
| DAN Dana Inc. | 1.60% | 1,611,500 | $54.2M | Add +102.3% |
| BTSG Brightspring Health Services | 1.46% | 1,158,970 | $49.4M | Add +27.6% |
| MTSI Macom Technology Solutions H | 1.42% | 215,886 | $47.9M | Add +20.6% |
| RMBS Rambus Inc. | 1.34% | 526,316 | $45.3M | Add +13.9% |
| CLH Clean Harbors Inc. | 1.22% | 144,355 | $41.4M | Add +23.5% |
| SITM Sitime Corp. | 1.22% | 119,281 | $41.2M | Add +12.1% |
| UCTT Ultra Clean Holdings Inc. | 1.18% | 640,476 | $39.8M | Add +1.9% |
| ECG Everus Construction Group | 1.14% | 326,533 | $38.6M | Add +25.7% |
| FTDR Frontdoor Inc. | 1.12% | 717,960 | $38.0M | Add +17.5% |
| CRS Carpenter Technology | 1.10% | 94,433 | $37.2M | Add +14.3% |
| SKYW Skywest Inc. | 1.06% | 392,499 | $36.0M | Add +2.7% |
| LSCC Lattice Semiconductor Corp. | 1.03% | 374,436 | $34.7M | Add +19.0% |
| GMED Globus Medical Inc. Class A | 1.00% | 392,200 | $33.8M | Add +45.3% |
| CAMT Camtek Ltd. | 1.00% | 222,780 | $33.8M | Add +1.8% |
| ARQT Arcutis Biotherapeutics Inc. | 0.95% | 1,365,941 | $32.2M | Add +69.0% |
| FLS Flowserve Corp. | 0.94% | 434,681 | $32.0M | Add +6.0% |
| SIMO Silicon Motion Technol-ADR | 0.94% | 282,550 | $31.7M | Add +19.6% |
| LTH Life Time Group Holdings Inc. | 0.92% | 1,160,500 | $31.3M | Add +9.6% |
| RSI Rush Street Interactive Inc. | 0.92% | 1,434,560 | $31.2M | Add +1.6% |
| FCFS Firstcash Holdings Inc. | 0.92% | 165,665 | $31.1M | Add +26.2% |
| FSLY Fastly Inc. Class A | 0.92% | 1,071,022 | $31.1M | Add +55.3% |
| TPC Tutor Perini Corp. | 0.90% | 393,900 | $30.4M | Add +1.7% |
| BROS Dutch Bros Inc. Class A | 0.90% | 598,493 | $30.3M | Add +48.0% |
| SEI Solaris Energy Infrastructur | 0.89% | 531,889 | $30.1M | Add +45.0% |
| MMSI Merit Medical Systems Inc. | 0.86% | 424,209 | $29.2M | Add +57.8% |
| FSS Federal Signal Corp. | 0.85% | 267,634 | $28.9M | Add +60.7% |
| AMSC American Superconductor Corp. | 0.85% | 849,900 | $28.8M | Add +1.7% |
| MRCY Mercury Systems Inc. | 0.84% | 391,023 | $28.5M | Reduce -5.6% |
| ACA Arcosa Inc. | 0.84% | 267,700 | $28.4M | Add +20.8% |
| OSIS Osi Systems Inc. | 0.84% | 106,593 | $28.3M | Add +5.1% |
| CNR Core Natural Resources Inc. | 0.83% | 269,800 | $28.3M | Add +51.2% |
| WAY Waystar Holding Corp. | 0.83% | 1,167,474 | $28.1M | Add +38.9% |
| EHC Encompass Health Corp. | 0.83% | 289,485 | $28.0M | Reduce -19.4% |
| VCYT Veracyte Inc. | 0.80% | 839,834 | $27.1M | Add +15.6% |
| AIR Aar Corp. | 0.79% | 245,125 | $26.8M | Reduce -10.1% |
| ICUI Icu Medical Inc. | 0.78% | 203,710 | $26.3M | Add +21.2% |
| LFUS Littelfuse Inc. | 0.72% | 71,800 | $24.4M | Add +15.3% |
| PRIM Primoris Services Corp. | 0.70% | 166,100 | $23.8M | Add +1.7% |
| RELY Remitly Global Inc. | 0.67% | 1,454,300 | $22.8M | Add +45.0% |
| G Genpact Ltd. | 0.67% | 606,832 | $22.6M | Add +16.3% |
| AIZ Assurant Inc. | 0.66% | 102,300 | $22.3M | Add +23.3% |
| BLBD Blue Bird Corp. | 0.65% | 389,238 | $22.1M | Add +1.7% |
| IMAX Imax Corp. | 0.65% | 577,139 | $21.9M | Reduce -11.5% |
| LEVI Levi Strauss & Co. Class A | 0.64% | 1,167,300 | $21.6M | Add +17.4% |
| ATEC Alphatec Holdings Inc. | 0.61% | 1,908,293 | $20.8M | Add +90.8% |
| LASR Nlight Inc. | 0.61% | 363,010 | $20.7M | Add +1.9% |
| EYE National Vision Holdings Inc. | 0.61% | 797,780 | $20.7M | Add +1.7% |
| ABCB Ameris Bancorp | 0.61% | 263,500 | $20.6M | Add +68.5% |
| LIVN Livanova PLC | 0.60% | 321,900 | $20.5M | Add +51.6% |
| DRS Leonardo DRS Inc. | 0.59% | 449,500 | $20.0M | New |
| URBN Urban Outfitters Inc. | 0.59% | 314,792 | $19.9M | Add +9.9% |
| INDV Indivior Pharmaceuticals Inc. | 0.59% | 653,413 | $19.9M | Add +53.8% |
| LOPE Grand Canyon Education Inc. | 0.59% | 116,900 | $19.9M | Add +17.1% |
| VISN Vistance Networks Inc. | 0.59% | 1,092,012 | $19.9M | Add +13.6% |
| MTDR Matador Resources Co. | 0.58% | 312,700 | $19.8M | Add +23.2% |
| VIAV Viavi Solutions Inc. | 0.58% | 593,200 | $19.7M | Add +16.8% |
| CHYM Chime Financial Inc. Class A | 0.57% | 1,035,530 | $19.4M | New |
| PEGA Pegasystems Inc. | 0.57% | 455,290 | $19.4M | Add +7.2% |
| CPRX Catalyst Pharmaceuticals Inc. | 0.57% | 780,570 | $19.3M | Add +33.0% |
| QTWO Q2 Holdings Inc. filed as Q2 HLDGS INC | 0.55% | 394,629 | $18.7M | Add +17.1% |
| POWL Powell Industries Inc. | 0.55% | 34,157 | $18.5M | Reduce -29.9% |
| IRTC Irhythm Holdings Inc. | 0.54% | 156,004 | $18.4M | Add +30.3% |
| BOX Box Inc. Class A | 0.54% | 771,520 | $18.2M | Add +18.3% |
| AGX Argan Inc. | 0.54% | 33,322 | $18.1M | Add +1.1% |
| HNGE Hinge Health Inc. Class A | 0.53% | 465,766 | $18.0M | New |
| NYT New York Times Co. Class A | 0.52% | 211,650 | $17.7M | Reduce -30.1% |
| AEO American Eagle Outfitters | 0.52% | 1,044,900 | $17.4M | Add +28.3% |
| ALHC Alignment Healthcare Inc. | 0.50% | 966,600 | $17.0M | Add +29.3% |
| ANIP Ani Pharmaceuticals Inc. | 0.50% | 221,386 | $17.0M | Add +17.2% |
| NVST Envista Holdings Corp. | 0.50% | 665,400 | $16.9M | New |
| WGS Genedx Holdings Corp. | 0.50% | 261,370 | $16.8M | Add +31.5% |
| SPXC SPX Technologies Inc. | 0.49% | 83,441 | $16.7M | Add +8.5% |
| SHAK Shake Shack Inc. Class A | 0.49% | 187,570 | $16.6M | New |
| CALX Calix Inc. | 0.48% | 335,030 | $16.4M | Add +37.0% |
| SGHC Super Group SGHC Ltd. | 0.48% | 1,514,400 | $16.4M | Add +19.4% |
| EZPW Ezcorp Inc. Class A | 0.48% | 639,400 | $16.2M | Add +1.8% |
| LMAT Lemaitre Vascular Inc. | 0.48% | 148,601 | $16.2M | Add +27.8% |
| AEIS Advanced Energy Industries | 0.47% | 49,183 | $15.9M | Add +23.9% |
| ZWS Zurn Elkay Water Solutions C | 0.47% | 352,183 | $15.8M | Add +32.4% |
| FN Fabrinet | 0.47% | 30,263 | $15.8M | Add +20.1% |
| KNSA Kiniksa Pharmaceuticals Inte | 0.45% | 318,634 | $15.3M | Add +1.9% |
| PAHC Phibro Animal Health Corp. Class A | 0.45% | 277,100 | $15.3M | Add +32.1% |
| DIOD Diodes Inc. | 0.45% | 224,300 | $15.3M | Add +47.7% |
| AMBA Ambarella Inc. | 0.45% | 295,185 | $15.2M | Reduce -52.2% |
| MD Pediatrix Medical Group Inc. | 0.44% | 701,087 | $15.0M | Add +25.2% |
| MGY Magnolia Oil & Gas Corp. Class A | 0.42% | 454,466 | $14.3M | Add +20.8% |
| SKWD Skyward Specialty Insurance | 0.42% | 327,100 | $14.3M | Add +37.7% |
| HALO Halozyme Therapeutics Inc. | 0.42% | 219,930 | $14.2M | Add +87.0% |
| LQDA Liquidia Corp. | 0.41% | 372,100 | $14.0M | Add +13.0% |
| ARLO Arlo Technologies Inc. | 0.41% | 982,300 | $14.0M | New |
| HQY Healthequity Inc. | 0.41% | 166,641 | $13.9M | Add +17.7% |
| PUMP Propetro Holding Corp. | 0.41% | 965,500 | $13.9M | Add +1.9% |
| ZETA Zeta Global Holdings Corp. Class A | 0.41% | 871,060 | $13.9M | Add +13.6% |
| MIR Mirion Technologies Inc. | 0.41% | 744,267 | $13.8M | Add +22.4% |
Other holdings (1): bonds, preferreds, convertibles and warrants · $260K (not counted above)
| Security | Class | Shares / Principal | Value | Change |
|---|---|---|---|---|
| WELLS FARGO & COMPANY (WFC 7.5 PERP L) | PERP PFD CNV A | 225 | $260K | No change |
Total filed on the 13F, all lines: $3.4B.
Portfolio Sells Q4 2025 → Q1 2026
| AMBA Ambarella Inc. | Reduce -52.2% | 0.45% | −1.15 |
| FRSH Freshworks Inc. Class A | Reduce -97.2% | 0.01% | −0.91 |
| CARG Cargurus Inc. | Sold out | 0.00% | −0.73 |
| SXT Sensient Technologies Corp. | Sold out | 0.00% | −0.65 |
| GENI Genius Sports Ltd. | Sold out | 0.00% | −0.64 |
| ACIW Aci Worldwide Inc. | Sold out | 0.00% | −0.58 |
| EHC Encompass Health Corp. | Reduce -19.4% | 0.83% | −0.57 |
| CVLT Commvault Systems Inc. | Sold out | 0.00% | −0.51 |
| TPB Turning Point Brands Inc. | Sold out | 0.00% | −0.41 |
| WK Workiva Inc. | Sold out | 0.00% | −0.40 |
| GDOT Green Dot Corp. Class A | Sold out | 0.00% | −0.36 |
| IBEX Ibex Ltd. | Reduce -95.8% | 0.01% | −0.33 |
| ATRC Atricure Inc. | Sold out | 0.00% | −0.32 |
| REVG Rev Group Inc. | Sold out | 0.00% | −0.31 |
| BBW Build-A-Bear Workshop Inc. | Sold out | 0.00% | −0.30 |
| FRME First Merchants Corp. | Sold out | 0.00% | −0.27 |
| WEAV Weave Communications Inc. | Reduce -92.7% | 0.01% | −0.27 |
| MRCY Mercury Systems Inc. | Reduce -5.6% | 0.84% | −0.26 |
| MBUU Malibu Boats Inc. Class A | Sold out | 0.00% | −0.25 |
| NYT New York Times Co. Class A | Reduce -30.1% | 0.52% | −0.24 |
| HWKN Hawkins Inc. | Sold out | 0.00% | −0.24 |
| IMAX Imax Corp. | Reduce -11.5% | 0.65% | −0.23 |
| PGY Pagaya Technologies Ltd. Class A | Sold out | 0.00% | −0.23 |
| COCO The Vita Coco Co. Inc. | Reduce -33.1% | 0.22% | −0.23 |
| AIOT Powerfleet Inc. | Sold out | 0.00% | −0.21 |
| LYTS Lsi Industries Inc. | Sold out | 0.00% | −0.12 |
| MTRX Matrix Service Co. | Sold out | 0.00% | −0.10 |
| BLZE Backblaze Inc. Class A | Sold out | 0.00% | −0.09 |
| CECO Ceco Environmental Corp. | Reduce -7.2% | 0.24% | −0.08 |
| SHOP Shopify Inc. Class A | Sold out | 0.00% | −0.08 |
| FUTU Futu Holdings Ltd.-ADR | Reduce -59.1% | 0.02% | −0.05 |
| LINC Lincoln Educational Services | Reduce -39.0% | 0.23% | −0.05 |
| MU Micron Technology Inc. | Reduce -84.4% | 0.01% | −0.04 |
| AIR Aar Corp. | Reduce -10.1% | 0.79% | −0.03 |
| POWL Powell Industries Inc. | Reduce -29.9% | 0.55% | −0.02 |
| BNY Bank of New York Mellon Corp. | Reduce -1.7% | 0.01% | −0.00 |
| WMT Walmart Inc. | Reduce -2.3% | 0.01% | −0.00 |
| CAT Caterpillar Inc. | Reduce -8.9% | 0.01% | −0.00 |
| LITE Lumentum Holdings Inc. | Reduce -5.2% | 5.53% | +1.74 |
Portfolio Buys Q4 2025 → Q1 2026
| AAOI Applied Optoelectronics Inc. | Add +15.2% | 5.87% | +3.27 |
| DOCN Digitalocean Holdings Inc. | Add +19.1% | 2.35% | +0.98 |
| DAN Dana Inc. | Add +102.3% | 1.60% | +0.91 |
| FSLY Fastly Inc. Class A | Add +55.3% | 0.92% | +0.66 |
| UCTT Ultra Clean Holdings Inc. | Add +1.9% | 1.18% | +0.59 |
| DRS Leonardo DRS Inc. | New | 0.59% | +0.59 |
| CHYM Chime Financial Inc. Class A | New | 0.57% | +0.57 |
| HNGE Hinge Health Inc. Class A | New | 0.53% | +0.53 |
| NVST Envista Holdings Corp. | New | 0.50% | +0.50 |
| SHAK Shake Shack Inc. Class A | New | 0.49% | +0.49 |
| ARLO Arlo Technologies Inc. | New | 0.41% | +0.41 |
| NVMI Nova Ltd. | Add +21.8% | 1.77% | +0.41 |
| MOG.A Moog Inc. Class A | New | 0.39% | +0.39 |
| ATEN A10 Networks Inc. | New | 0.34% | +0.34 |
| SBCF Seacoast Banking Corp. | New | 0.34% | +0.34 |
| ECG Everus Construction Group | Add +25.7% | 1.14% | +0.33 |
| MTSI Macom Technology Solutions H | Add +20.6% | 1.42% | +0.30 |
| AMPX Amprius Technologies Inc. | New | 0.29% | +0.29 |
| SEI Solaris Energy Infrastructur | Add +45.0% | 0.89% | +0.27 |
| CNR Core Natural Resources Inc. | Add +51.2% | 0.83% | +0.26 |
| VIAV Viavi Solutions Inc. | Add +16.8% | 0.58% | +0.25 |
| THR Thermon Group Holdings Inc. | New | 0.23% | +0.23 |
| CLH Clean Harbors Inc. | Add +23.5% | 1.22% | +0.22 |
| APEI American Public Education | New | 0.22% | +0.22 |
| BW Babcock & Wilcox Enterpr | New | 0.22% | +0.22 |
| BTSG Brightspring Health Services | Add +27.6% | 1.46% | +0.22 |
| FSS Federal Signal Corp. | Add +60.7% | 0.85% | +0.19 |
| MTDR Matador Resources Co. | Add +23.2% | 0.58% | +0.19 |
| ABCB Ameris Bancorp | Add +68.5% | 0.61% | +0.18 |
| LSCC Lattice Semiconductor Corp. | Add +19.0% | 1.03% | +0.18 |
| DIOD Diodes Inc. | Add +47.7% | 0.45% | +0.18 |
| KN Knowles Corp. | New | 0.18% | +0.18 |
| RELY Remitly Global Inc. | Add +45.0% | 0.67% | +0.17 |
| CNXN PC Connection Inc. | New | 0.17% | +0.17 |
| PAHC Phibro Animal Health Corp. Class A | Add +32.1% | 0.45% | +0.17 |
| AEIS Advanced Energy Industries | Add +23.9% | 0.47% | +0.16 |
| AGX Argan Inc. | Add +1.1% | 0.54% | +0.16 |
| FCFS Firstcash Holdings Inc. | Add +26.2% | 0.92% | +0.15 |
| CRS Carpenter Technology | Add +14.3% | 1.10% | +0.15 |
| CAMT Camtek Ltd. | Add +1.8% | 1.00% | +0.15 |
| LFUS Littelfuse Inc. | Add +15.3% | 0.72% | +0.14 |
| BRCB Black Rock Coffee Bar Inc. Class A | New | 0.14% | +0.14 |
| SIMO Silicon Motion Technol-ADR | Add +19.6% | 0.94% | +0.14 |
| GMED Globus Medical Inc. Class A | Add +45.3% | 1.00% | +0.14 |
| RCKY Rocky Brands Inc. | New | 0.14% | +0.14 |
| LMAT Lemaitre Vascular Inc. | Add +27.8% | 0.48% | +0.13 |
| HALO Halozyme Therapeutics Inc. | Add +87.0% | 0.42% | +0.13 |
| LIVN Livanova PLC | Add +51.6% | 0.60% | +0.13 |
| MGY Magnolia Oil & Gas Corp. Class A | Add +20.8% | 0.42% | +0.12 |
| LASR Nlight Inc. | Add +1.9% | 0.61% | +0.12 |
All Filings
| Quarter | Positions | 13F Reported Value | Top Holdings |
|---|---|---|---|
| Q2 2026 | 175 | $4.8B | CRDO, AAOI, DOCN, SIMO, UCTT |
| Q1 2026 | 179 | $3.4B | AAOI, LITE, CRDO, DOCN, SN |
| Q4 2025 | 178 | $2.7B | LITE, CRDO, AAOI, SN, AMBA |
| Q3 2025 | 183 | $2.6B | CRDO, LITE, RMBS, AMBA, SN |
| Q2 2025 | 185 | $2.3B | CRDO, ADMA, AAOI, SN, EHC |
| Q1 2025 | 192 | $2.0B | ADMA, CRDO, SN, EHC, DOCS |
| Q4 2024 | 196 | $2.1B | CRDO, ADMA, SN, ZETA, SKYW |
| Q3 2024 | 206 | $2.0B | ADMA, SN, ZETA, EHC, WFRD |
| Q2 2024 | 197 | $1.6B | WFRD, CSTM, SN, ONTO, TMDX |
| Q1 2024 | 196 | $1.4B | CSTM, WFRD, ACLS, ONTO, ATEC |