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 | |
|---|---|---|---|---|---|---|
6351
Janus Henderson AAA CLO ETF
JAAA
$29B
| $22.9K | ﹤0.01% |
453
+350
| +340% | +$17.7K |
|
6352
ACI Worldwide
ACIW
$5.83B
| $22.9K | ﹤0.01% |
478
+66
| +16% | +$3.2K |
|
6353
CALL
Global Water Resources
GWRS
$206M
| $22.8K | ﹤0.01% |
2,700
+2,600
| +2,600% | +$24.5K |
|
6354
PUT
BrightView Holdings
BV
$1.22B
| $22.8K | ﹤0.01% |
1,800
-300
| -14% | -$3.81K |
|
6355
CALL
Artivion
AORT
$1.3B
| $22.8K | ﹤0.01% |
500
| – | – |
|
6356
PUT
Westlake Chemical Partners
WLKP
$763M
| $22.8K | ﹤0.01% |
1,200
-700
| -37% | -$13.5K |
|
6357
State Street SPDR S&P 600 Small Cap Growth ETF
SLYG
$5.07B
| $22.8K | ﹤0.01% |
242
-4,875
| -95% | -$460K |
|
6358
CALL
Tenaya Therapeutics
TNYA
$161M
| $22.8K | ﹤0.01% |
32,000
+100
| +0.3% | +$136 |
|
6359
CALL
RXO
RXO
$3.34B
| $22.8K | ﹤0.01% |
1,800
+600
| +50% | +$8.85K |
|
6360
Marqeta
MQ
$1.83B
| $22.7K | ﹤0.01% |
+1,195
| New | +$23K |
|
6361
PUT
United States Brent Oil Fund
BNO
$781M
| $22.7K | ﹤0.01% |
800
-100
| -11% | -$2.89K |
|
6362
PUT
SIGA Technologies
SIGA
$235M
| $22.6K | ﹤0.01% |
3,700
-100
| -3% | -$711 |
|
|
HDSN
6363
CALL
Hudson Technologies
HDSN
$254M
| $22.6K | ﹤0.01% |
+3,300
| New | +$26K |
|
6364
CALL
OP Bancorp
OPBK
$232M
| $22.6K | ﹤0.01% |
1,600
| – | – |
|
6365
National CineMedia
NCMI
$376M
| $22.5K | ﹤0.01% |
5,795
-26,785
| -82% | -$111K |
|
6366
Transcat
TRNS
$799M
| $22.5K | ﹤0.01% |
+396
| New | +$24.7K |
|
6367
PUT
iMGP DBi Managed Futures Strategy ETF
DBMF
$3.98B
| $22.4K | ﹤0.01% |
800
-1,000
| -56% | -$28.5K |
|
|
CCCX
6368
DELISTED
Churchill Capital Corp X
CCCX
| $22.4K | ﹤0.01% |
1,434
-12,527
| -90% | -$211K |
|
6369
CALL
Riskified
RSKD
$694M
| $22.4K | ﹤0.01% |
+4,500
| New | +$21.7K |
|
6370
CALL
La-Z-Boy
LZB
$1.58B
| $22.4K | ﹤0.01% |
600
-3,600
| -86% | -$126K |
|
6371
Clarus
CLAR
$123M
| $22.4K | ﹤0.01% |
6,675
-5
| -0.1% | -$17 |
|
6372
CALL
Dorchester Minerals
DMLP
$1.33B
| $22.4K | ﹤0.01% |
1,000
-38,700
| -97% | -$905K |
|
6373
Outset Medical
OM
$84.7M
| $22.3K | ﹤0.01% |
6,023
+5,812
| +2,755% | +$49.9K |
|
|
NVOX
6374
Defiance Daily Target 2x Long NVO ETF
NVOX
$38.6M
| $22.3K | ﹤0.01% |
1,018
-49
| -5% | -$1.14K |
|
6375
CALL
Boston Omaha
BOC
$428M
| $22.3K | ﹤0.01% |
1,800
+500
| +38% | +$6.51K |
|
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.