Oberweis Asset Management Inc./
In its 13F for Q1 2024 (holdings as of March 31, 2024, filed May 15, 2024), Oberweis Asset Management Inc./ reported 196 stock positions worth $1.4 billion. Its top holding was Constellium (CSTM) at 2.9% of the portfolio, followed by Weatherford International PL (WFRD, 1.9%) and Axcelis Technologies (ACLS, 1.7%). Compared with Q4 2023, it opened 33 new positions, sold out of 29, added to 115 and reduced 37. The biggest buy was a new position in Sharkninja (SN) and the biggest sale Aehr Test Systems (AEHR, shares −11%).
- Most Recent 13F
- Q2 2026
- Location
- LISLE, IL
- CIK
- 0000937886
- Portfolio Value
- $1.4B (Q1 2024)
- SEC Filing
- 0001213900-24-043291 ↗ filed May 15, 2024
Holdings Value
Holdings 196 stocks · $1.4B
| CSTM Constellium SE | 2.88% | 1,803,271 | $39.9M | Reduce -2.5% |
| WFRD Weatherford International PL | 1.85% | 222,100 | $25.6M | Reduce -7.5% |
| ACLS Axcelis Technologies Inc. | 1.69% | 209,339 | $23.3M | Reduce -14.7% |
| ONTO Onto Innovation Inc. | 1.40% | 106,930 | $19.4M | Add +139.8% |
| ATEC Alphatec Holdings Inc. | 1.38% | 1,385,880 | $19.1M | Reduce -13.8% |
| VRT Vertiv Holdings Co. Class A | 1.36% | 229,650 | $18.8M | Reduce -1.7% |
| ADMA Adma Biologics Inc. | 1.33% | 2,790,700 | $18.4M | Add +3.0% |
| AMPH Amphastar Pharmaceuticals Inc. | 1.33% | 417,865 | $18.3M | Add +22.8% |
| SKYW Skywest Inc. | 1.31% | 262,360 | $18.1M | Add +96.2% |
| EHC Encompass Health Corp. | 1.22% | 204,136 | $16.9M | Add +40.5% |
| SIMO Silicon Motion Technol-ADR | 1.21% | 217,400 | $16.7M | Add +184.6% |
| OSK Oshkosh Corp. | 1.21% | 133,827 | $16.7M | Add +35.3% |
| CLH Clean Harbors Inc. | 1.18% | 81,295 | $16.4M | Add +42.5% |
| AVAV Aerovironment Inc. | 1.13% | 101,570 | $15.6M | Add +45.5% |
| CAMT Camtek Ltd. | 1.08% | 178,180 | $14.9M | Add +2.1% |
| VCYT Veracyte Inc. | 1.08% | 671,700 | $14.9M | Add +2.3% |
| UCTT Ultra Clean Holdings Inc. | 1.06% | 319,600 | $14.7M | Add +29.3% |
| TMDX Transmedics Group Inc. | 1.06% | 198,200 | $14.7M | Reduce -6.9% |
| SN Sharkninja Inc. | 1.06% | 235,200 | $14.7M | New |
| ICFI Icf International Inc. | 1.06% | 96,900 | $14.6M | Add +46.6% |
| ESAB Esab Corp. | 1.03% | 129,200 | $14.3M | Add +63.3% |
| PSN Parsons Corp. | 1.03% | 172,140 | $14.3M | Add +29.4% |
| CROX Crocs Inc. | 0.99% | 95,400 | $13.7M | Add +90.8% |
| NXT Nextpower Inc. filed as NEXTRACKER INC | 0.96% | 235,700 | $13.3M | Add +128.4% |
| OLED Universal Display Corp. | 0.94% | 77,442 | $13.0M | Add +16.4% |
| ZETA Zeta Global Holdings Corp. Class A | 0.93% | 1,181,980 | $12.9M | Add +26.4% |
| ACMR Acm Research Inc. Class A | 0.93% | 441,130 | $12.9M | Add +12.1% |
| FLS Flowserve Corp. | 0.91% | 274,378 | $12.5M | Add +11.9% |
| HAE Haemonetics Corp. | 0.89% | 143,695 | $12.3M | Add +35.7% |
| ACHC Acadia Healthcare Co. Inc. | 0.87% | 151,650 | $12.0M | Add +68.1% |
| AEHR Aehr Test Systems | 0.87% | 967,852 | $12.0M | Reduce -11.3% |
| MMSI Merit Medical Systems Inc. | 0.86% | 156,490 | $11.9M | Add +46.1% |
| AAOI Applied Optoelectronics Inc. | 0.85% | 849,615 | $11.8M | Reduce -4.7% |
| CCS Century Communities Inc. | 0.85% | 121,200 | $11.7M | New |
| FCFS Firstcash Holdings Inc. | 0.85% | 91,700 | $11.7M | Add +23.6% |
| ITRI Itron Inc. | 0.84% | 125,600 | $11.6M | New |
| NEO Neogenomics Inc. | 0.84% | 737,200 | $11.6M | Add +87.7% |
| BLBD Blue Bird Corp. | 0.83% | 299,100 | $11.5M | Add +4.3% |
| ACIW Aci Worldwide Inc. | 0.83% | 344,562 | $11.4M | Add +138.8% |
| LIVN Livanova PLC | 0.82% | 202,500 | $11.3M | Add +172.9% |
| ITGR Integer Holdings Corp. | 0.82% | 96,700 | $11.3M | Add +36.2% |
| AXONICS INC | 0.82% | 163,570 | $11.3M | Reduce -8.3% |
| SLAB Silicon Laboratories Inc. | 0.81% | 78,000 | $11.2M | New |
| EVH Evolent Health Inc. Class A | 0.80% | 338,940 | $11.1M | Add +58.0% |
| AZEK The Azek Co. Inc. | 0.80% | 220,900 | $11.1M | New |
| FSS Federal Signal Corp. | 0.78% | 127,830 | $10.8M | Add +29.3% |
| INFA Informatica Inc. Class A | 0.78% | 309,000 | $10.8M | Add +69.7% |
| FORM Formfactor Inc. | 0.78% | 236,700 | $10.8M | Add +48.7% |
| CECO Ceco Environmental Corp. | 0.77% | 463,400 | $10.7M | Add +8.6% |
| STRL Sterling Infrastructure Inc. | 0.77% | 96,600 | $10.7M | Add +9.8% |
| YOU Clear Secure Inc. Class A | 0.77% | 500,500 | $10.6M | Add +64.9% |
| INSW International Seaways Inc. | 0.76% | 198,700 | $10.6M | Add +110.0% |
| WWD Woodward Inc. | 0.76% | 68,400 | $10.5M | Add +31.5% |
| JBI Janus International Group Inc. | 0.76% | 695,400 | $10.5M | Add +31.6% |
| RAMP Liveramp Holdings Inc. | 0.74% | 295,780 | $10.2M | Add +112.8% |
| VECO Veeco Instruments Inc. | 0.68% | 269,100 | $9.5M | Add +12.1% |
| PRIM Primoris Services Corp. | 0.65% | 209,900 | $8.9M | No change |
| DECK Deckers Outdoor Corp. | 0.64% | 9,420 | $8.9M | Reduce -21.8% |
| FTDR Frontdoor Inc. | 0.62% | 263,300 | $8.6M | Reduce -2.9% |
| AMSC American Superconductor Corp. | 0.62% | 634,400 | $8.6M | Add +68.8% |
| ELF Elf Beauty Inc. | 0.62% | 43,720 | $8.6M | Add +53.4% |
| MSA Msa Safety Inc. | 0.62% | 44,200 | $8.6M | Add +57.3% |
| GO Grocery Outlet Holding Corp. | 0.62% | 296,000 | $8.5M | Add +112.6% |
| SPXC SPX Technologies Inc. | 0.61% | 69,000 | $8.5M | Reduce -5.5% |
| CBT Cabot Corp. | 0.61% | 92,100 | $8.5M | New |
| AIZ Assurant Inc. | 0.61% | 45,000 | $8.5M | Add +46.6% |
| KWR Quaker Chemical Corporation | 0.60% | 40,500 | $8.3M | Add +50.0% |
| OSIS Osi Systems Inc. | 0.57% | 55,300 | $7.9M | Add +56.7% |
| IBP Installed Building Products | 0.57% | 30,400 | $7.9M | New |
| EZPW Ezcorp Inc. Class A | 0.56% | 685,500 | $7.8M | Add +4.6% |
| AVNW Aviat Networks Inc. | 0.55% | 199,307 | $7.6M | Add +54.3% |
| MMS Maximus Inc. | 0.54% | 89,700 | $7.5M | Add +48.5% |
| WING Wingstop Inc. | 0.53% | 20,000 | $7.3M | Add +25.8% |
| CPRX Catalyst Pharmaceuticals Inc. | 0.53% | 458,400 | $7.3M | Add +31.5% |
| PFBC Preferred Bank/Los Angeles | 0.53% | 95,000 | $7.3M | Add +6.0% |
| PLYA Playa Hotels & Resorts NV | 0.53% | 751,500 | $7.3M | Add +7.1% |
| ATI Ati Inc. | 0.53% | 141,900 | $7.3M | Add +38.4% |
| PLAB Photronics Inc. | 0.52% | 256,100 | $7.3M | Add +3.5% |
| WEAV Weave Communications Inc. | 0.51% | 609,400 | $7.0M | No change |
| LMB Limbach Holdings Inc. | 0.49% | 164,800 | $6.8M | Add +65.6% |
| CRDO Credo Technology Group Holdi | 0.49% | 321,900 | $6.8M | New |
| IPAR Interparfums Inc. | 0.49% | 48,300 | $6.8M | Reduce -0.2% |
| RXST Rxsight Inc. | 0.47% | 126,640 | $6.5M | Add +52.4% |
| RES RPC Inc. | 0.47% | 838,476 | $6.5M | Reduce -2.3% |
| MCRI Monarch Casino & Resort Inc. | 0.47% | 86,200 | $6.5M | Add +47.4% |
| GIII G-III Apparel Group Ltd. | 0.46% | 220,900 | $6.4M | Add +12.4% |
| KRYS Krystal Biotech Inc. | 0.46% | 35,700 | $6.4M | New |
| FIX Comfort Systems USA Inc. | 0.46% | 19,800 | $6.3M | Add +11.9% |
| PETQ Petiq Inc. | 0.45% | 340,700 | $6.2M | Add +11.9% |
| MOD Modine Manufacturing Co. | 0.44% | 64,500 | $6.1M | Reduce -25.4% |
| ANF Abercrombie & Fitch Co. Class A | 0.44% | 48,100 | $6.0M | Reduce -12.6% |
| TREX Trex Company Inc. | 0.43% | 60,100 | $6.0M | Add +49.9% |
| AORT Artivion Inc. | 0.43% | 282,400 | $6.0M | Add +9.5% |
| ALGM Allegro Microsystems Inc. | 0.43% | 221,280 | $6.0M | Reduce -14.2% |
| PRMW Primo Water Corp. | 0.43% | 323,500 | $5.9M | Add +34.3% |
| LOPE Grand Canyon Education Inc. | 0.43% | 43,200 | $5.9M | Add +61.2% |
| UPWK Upwork Inc. | 0.42% | 469,200 | $5.8M | Add +18.2% |
| VTLE Vital Energy Inc. | 0.42% | 109,400 | $5.7M | Add +9.7% |
| DVAX Dynavax Technologies Corp. | 0.42% | 462,700 | $5.7M | Add +10.8% |
| EOLS Evolus Inc. | 0.40% | 397,300 | $5.6M | Add +7.0% |
Portfolio Sells Q4 2023 → Q1 2024
| AEHR Aehr Test Systems | Reduce -11.3% | 0.87% | −1.83 |
| PERI Perion Network Ltd. | Sold out | 0.00% | −1.31 |
| ACLS Axcelis Technologies Inc. | Reduce -14.7% | 1.69% | −1.28 |
| ATEC Alphatec Holdings Inc. | Reduce -13.8% | 1.38% | −0.88 |
| BELFB Bel Fuse Inc. Class B | Sold out | 0.00% | −0.77 |
| AAOI Applied Optoelectronics Inc. | Reduce -4.7% | 0.85% | −0.75 |
| POWI Power Integrations Inc. | Sold out | 0.00% | −0.75 |
| MGPI MGP Ingredients Inc. | Sold out | 0.00% | −0.59 |
| THR Thermon Group Holdings Inc. | Sold out | 0.00% | −0.58 |
| CSTM Constellium SE | Reduce -2.5% | 2.88% | −0.56 |
| VC Visteon Corp. | Sold out | 0.00% | −0.51 |
| SMCI Super Micro Computer Inc. | Sold out | 0.00% | −0.51 |
| TMDX Transmedics Group Inc. | Reduce -6.9% | 1.06% | −0.51 |
| CVSA Covista Inc. | Sold out | 0.00% | −0.47 |
| ROVR Rover Group Inc. | Sold out | 0.00% | −0.47 |
| TAST Carrols Restaurant Group Inc. | Sold out | 0.00% | −0.46 |
| NVTS Navitas Semiconductor Corp. | Reduce -15.9% | 0.28% | −0.44 |
| VVX V2X Inc. | Sold out | 0.00% | −0.44 |
| FSLY Fastly Inc. Class A | Sold out | 0.00% | −0.41 |
| OPCH Option Care Health Inc. | Sold out | 0.00% | −0.36 |
| WFRD Weatherford International PL | Reduce -7.5% | 1.85% | −0.33 |
| BJRI Bj's Restaurants Inc. | Reduce -57.2% | 0.17% | −0.33 |
| HALO Halozyme Therapeutics Inc. | Sold out | 0.00% | −0.33 |
| HNI Hni Corp. | Reduce -46.1% | 0.27% | −0.33 |
| QLYS Qualys Inc. | Sold out | 0.00% | −0.32 |
| CDRE Cadre Holdings Inc. | Sold out | 0.00% | −0.31 |
| ALGM Allegro Microsystems Inc. | Reduce -14.2% | 0.43% | −0.30 |
| MGRC McGrath Rentcorp | Sold out | 0.00% | −0.29 |
| FN Fabrinet | Reduce -34.0% | 0.30% | −0.29 |
| HFWA Heritage Financial Corp. | Sold out | 0.00% | −0.28 |
| MHO M/I Homes Inc. | Reduce -25.8% | 0.36% | −0.27 |
| FTDR Frontdoor Inc. | Reduce -2.9% | 0.62% | −0.27 |
| CAL Caleres Inc. | Sold out | 0.00% | −0.25 |
| PLUS Eplus Inc. | Sold out | 0.00% | −0.25 |
| ATRC Atricure Inc. | Sold out | 0.00% | −0.23 |
| HIBB Hibbett Inc. | Sold out | 0.00% | −0.23 |
| PDD PDD Holdings Inc. | Reduce -42.0% | 0.12% | −0.22 |
| AXONICS INC | Reduce -8.3% | 0.82% | −0.22 |
| MIRM Mirum Pharmaceuticals Inc. | Sold out | 0.00% | −0.21 |
| PDFS PDF Solutions Inc. | Sold out | 0.00% | −0.21 |
| PRLB Proto Labs Inc. | Reduce -16.9% | 0.25% | −0.17 |
| JELD Jeld-Wen Holding Inc. | Reduce -26.0% | 0.30% | −0.16 |
| HEES H&E Equipment Services Inc. | Reduce -29.7% | 0.32% | −0.16 |
| IPAR Interparfums Inc. | Reduce -0.2% | 0.49% | −0.16 |
| RES RPC Inc. | Reduce -2.3% | 0.47% | −0.11 |
| FLL Full House Resorts Inc. | Sold out | 0.00% | −0.11 |
| DECK Deckers Outdoor Corp. | Reduce -21.8% | 0.64% | −0.11 |
| MNSO Miniso Group Holding Ltd.-ADR | Reduce -62.7% | 0.04% | −0.11 |
| OXM Oxford Industries Inc. | Reduce -25.7% | 0.19% | −0.10 |
| SPXC SPX Technologies Inc. | Reduce -5.5% | 0.61% | −0.07 |
Portfolio Buys Q4 2023 → Q1 2024
| SN Sharkninja Inc. | New | 1.06% | +1.06 |
| CCS Century Communities Inc. | New | 0.85% | +0.85 |
| ITRI Itron Inc. | New | 0.84% | +0.84 |
| SLAB Silicon Laboratories Inc. | New | 0.81% | +0.81 |
| AZEK The Azek Co. Inc. | New | 0.80% | +0.80 |
| SIMO Silicon Motion Technol-ADR | Add +184.6% | 1.21% | +0.77 |
| ONTO Onto Innovation Inc. | Add +139.8% | 1.40% | +0.77 |
| SKYW Skywest Inc. | Add +96.2% | 1.31% | +0.66 |
| CBT Cabot Corp. | New | 0.61% | +0.61 |
| IBP Installed Building Products | New | 0.57% | +0.57 |
| CROX Crocs Inc. | Add +90.8% | 0.99% | +0.56 |
| NXT Nextpower Inc. | Add +128.4% | 0.96% | +0.51 |
| CRDO Credo Technology Group Holdi | New | 0.49% | +0.49 |
| LIVN Livanova PLC | Add +172.9% | 0.82% | +0.46 |
| KRYS Krystal Biotech Inc. | New | 0.46% | +0.46 |
| ACIW Aci Worldwide Inc. | Add +138.8% | 0.83% | +0.42 |
| ESAB Esab Corp. | Add +63.3% | 1.03% | +0.40 |
| RSI Rush Street Interactive Inc. | New | 0.37% | +0.37 |
| INSW International Seaways Inc. | Add +110.0% | 0.76% | +0.36 |
| CLBT Cellebrite Di Ltd. | New | 0.32% | +0.32 |
| OSCR Oscar Health Inc. Class A | New | 0.32% | +0.32 |
| EHC Encompass Health Corp. | Add +40.5% | 1.22% | +0.32 |
| AVAV Aerovironment Inc. | Add +45.5% | 1.13% | +0.31 |
| EXLS Exlservice Holdings Inc. | New | 0.31% | +0.31 |
| THRM Gentherm Inc. | New | 0.31% | +0.31 |
| SFM Sprouts Farmers Market Inc. | New | 0.30% | +0.30 |
| DUOL Duolingo | New | 0.30% | +0.30 |
| INFA Informatica Inc. Class A | Add +69.7% | 0.78% | +0.30 |
| IMAX Imax Corp. | New | 0.28% | +0.28 |
| UCTT Ultra Clean Holdings Inc. | Add +29.3% | 1.06% | +0.28 |
| GO Grocery Outlet Holding Corp. | Add +112.6% | 0.62% | +0.27 |
| BLZE Backblaze Inc. Class A | New | 0.26% | +0.26 |
| CLH Clean Harbors Inc. | Add +42.5% | 1.18% | +0.26 |
| PSN Parsons Corp. | Add +29.4% | 1.03% | +0.26 |
| ARLO Arlo Technologies Inc. | New | 0.25% | +0.25 |
| RAMP Liveramp Holdings Inc. | Add +112.8% | 0.74% | +0.25 |
| NEO Neogenomics Inc. | Add +87.7% | 0.84% | +0.25 |
| ELF Elf Beauty Inc. | Add +53.4% | 0.62% | +0.24 |
| ICFI Icf International Inc. | Add +46.6% | 1.06% | +0.23 |
| AMSC American Superconductor Corp. | Add +68.8% | 0.62% | +0.23 |
| ACHC Acadia Healthcare Co. Inc. | Add +68.1% | 0.87% | +0.22 |
| ACMR Acm Research Inc. Class A | Add +12.1% | 0.93% | +0.21 |
| OSK Oshkosh Corp. | Add +35.3% | 1.21% | +0.21 |
| ARIS WATER SOLUTIONS INC-A | New | 0.20% | +0.20 |
| ADMA Adma Biologics Inc. | Add +3.0% | 1.33% | +0.19 |
| MTRX Matrix Service Co. | New | 0.19% | +0.19 |
| YOU Clear Secure Inc. Class A | Add +64.9% | 0.77% | +0.19 |
| SG Sweetgreen Inc. Class A | New | 0.18% | +0.18 |
| MSA Msa Safety Inc. | Add +57.3% | 0.62% | +0.18 |
| AXGN Axogen Inc. | New | 0.17% | +0.17 |
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 |