Simplex Trading Portfolio holdings
Simplex Trading, founded in 2004 and headquartered in Chicago, Illinois, is a technology-driven proprietary trading firm specializing in market-making and liquidity provision, primarily in U.S. equity options and futures options. Leveraging advanced proprietary software and data-driven analysis, the firm optimizes trading strategies and develops innovative solutions to capitalize on financial market opportunities, maintaining a competitive edge through automation and a collaborative team of technologists and traders. With a workforce exceeding 300 and led by CEO Erik Swanson since 2014, Simplex operates with a low-ego, high-intelligence culture, focusing on minimal bureaucracy and rapid execution, while also making strategic venture capital investments in fintech startups. Recognized as a top workplace in Chicago by Built In’s 2025 awards, Simplex continues to evolve, blending cutting-edge technology with a commitment to market efficiency and growth.
Top Buys
| Rank | Stock | Value |
|---|---|---|
| 1 |
Netflix
NFLX
|
+$73.1M |
| 2 |
Western Digital
WDC
|
+$51.8M |
| 3 |
iShares Semiconductor ETF
SOXX
|
+$46M |
| 4 |
Meta Platforms (Facebook)
META
|
+$41.8M |
| 5 |
Alibaba
BABA
|
+$37.1M |
Top Sells
| Rank | Stock | Value |
|---|---|---|
| 1 |
NVIDIA
NVDA
|
+$262M |
| 2 |
Microsoft
MSFT
|
+$194M |
| 3 |
iShares Russell 2000 ETF
IWM
|
+$149M |
| 4 |
Apple
AAPL
|
+$119M |
| 5 |
Amazon
AMZN
|
+$107M |
Sector Composition
| Rank | Sector | Weight |
|---|---|---|
| 1 | Technology | 0.59% |
| 2 | Consumer Discretionary | 0.21% |
| 3 | Healthcare | 0.2% |
| 4 | Industrials | 0.18% |
| 5 | Communication Services | 0.16% |
| Name | Market Value | Portfolio Weight | Shares or Principal |
Change in Stake | Capital Flow | |
|---|---|---|---|---|---|---|
5351
CALL
Angi Inc
ANGI
$229M
| $69.8K | ﹤0.01% |
5,400
-4,100
| -43% | -$52.8K |
|
|
MREO
5352
CALL
Mereo BioPharma
MREO
$54.7M
| $69.8K | ﹤0.01% |
167,300
+120,100
| +254% | +$229K |
|
5353
Sally Beauty Holdings
SBH
$1.43B
| $69.6K | ﹤0.01% |
+4,884
| New | +$73.6K |
|
5354
CALL
Beam Global
BEEM
$23.3M
| $69.5K | ﹤0.01% |
46,300
+36,200
| +358% | +$83.2K |
|
|
DGXX
5355
PUT
Digi Power X Inc
DGXX
$363M
| $69.4K | ﹤0.01% |
+27,200
| New | +$102K |
|
5356
PUT
Prosperity Bancshares
PB
$8.97B
| $69.1K | ﹤0.01% |
+1,000
| New | +$67.5K |
|
5357
Virtus InfraCap US Preferred Stock ETF
PFFA
$2.45B
| $68.9K | ﹤0.01% |
+3,199
| New | +$69K |
|
5358
Kanzhun
BZ
$7.27B
| $68.9K | ﹤0.01% |
+3,379
| New | +$73K |
|
5359
CALL
Calix
CALX
$2.26B
| $68.8K | ﹤0.01% |
1,300
-800
| -38% | -$46.6K |
|
5360
CALL
LGI Homes
LGIH
$1.27B
| $68.7K | ﹤0.01% |
1,600
+100
| +7% | +$4.69K |
|
5361
CALL
Douglas Dynamics
PLOW
$1.02B
| $68.6K | ﹤0.01% |
+2,100
| New | +$66.4K |
|
5362
Aemetis
AMTX
$106M
| $68.5K | ﹤0.01% |
49,313
-47,530
| -49% | -$95.6K |
|
5363
KULR Technology Group
KULR
$123M
| $68.5K | ﹤0.01% |
+23,155
| New | +$85K |
|
5364
PUT
Rigel Pharmaceuticals
RIGL
$681M
| $68.5K | ﹤0.01% |
1,600
-5,400
| -77% | -$204K |
|
5365
PUT
Idaho Strategic Resources
IDR
$444M
| $68.5K | ﹤0.01% |
1,700
-1,500
| -47% | -$57.3K |
|
5366
Cars.com
CARS
$662M
| $68.5K | ﹤0.01% |
5,614
-34,174
| -86% | -$397K |
|
5367
CALL
Accel Entertainment
ACEL
$978M
| $68.5K | ﹤0.01% |
+6,000
| New | +$63.2K |
|
|
ABX
5368
PUT
Abacus Global Management
ABX
$989M
| $68.4K | ﹤0.01% |
8,000
+100
| +1% | +$658 |
|
5369
BioAtla
BCAB
$5.46M
| $68.4K | ﹤0.01% |
2,408
+1,685
| +233% | +$66.1K |
|
5370
Coherus Oncology
CHRS
$217M
| $68.2K | ﹤0.01% |
48,044
-10,779
| -18% | -$15.7K |
|
5371
PUT
Carter's
CRI
$1.42B
| $68.1K | ﹤0.01% |
2,100
-5,800
| -73% | -$181K |
|
5372
CALL
CDW
CDW
$18.9B
| $68.1K | ﹤0.01% |
500
-1,100
| -69% | -$162K |
|
5373
Compañía de Cervecerías Unidas
CCU
$2.12B
| $68K | ﹤0.01% |
5,331
-718
| -12% | -$9.08K |
|
5374
CALL
Omnicell
OMCL
$1.61B
| $68K | ﹤0.01% |
1,500
+300
| +25% | +$11K |
|
5375
CALL
Inogen
INGN
$175M
| $67.9K | ﹤0.01% |
+10,100
| New | +$75.8K |
|
Similar funds
Simplex Trading's Q4 2025 Portfolio in Review
As of Q4 2025, Simplex Trading held 10,526 positions worth $177B, down 9% from $195B the previous quarter. Its ten largest holdings account for 49% of the portfolio.
Simplex Trading withdrew a net $23.2B in Q4 2025, closing 2,184 positions and reducing 4,088 holdings. Its most notable exit was iShares Russell 2000 ETF, an estimated $149M position sold in full.
By sector, the portfolio is most concentrated in Technology at 0.59% of assets, down from 0.79% a quarter earlier, followed by Consumer Discretionary and Healthcare.
Against the trend, Simplex Trading opened a new position in Western Digital worth $58.9M.
- Simplex Trading's largest Q4 2025 buy was Western Digital: 341,762 shares worth $58.9M.
- Simplex Trading added most to Netflix in Q4 2025, an estimated $73.1M increase.
- Simplex Trading's biggest Q4 2025 reduction was NVIDIA, cutting an estimated $262M.
- Simplex Trading fully exited iShares Russell 2000 ETF in Q4 2025, selling an estimated $149M.
- Simplex Trading's ten largest holdings make up 49% of its $177B portfolio in Q4 2025.
- Simplex Trading opened 1,476 new positions and closed 2,184 in Q4 2025.
- Simplex Trading's portfolio value fell 9% quarter-over-quarter to $177B.
Based on Simplex Trading's 13F filing for Q4 2025, filed 11 Feb 2026.