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 | |
|---|---|---|---|---|---|---|
1301
PUT
Crown Castle
CCI
$32.8B
| $4.78M | ﹤0.01% |
53,800
+9,900
| +23% | +$911K |
|
1302
CALL
Quantum Computing Inc
QUBT
$1.68B
| $4.78M | ﹤0.01% |
466,000
-689,100
| -60% | -$9.81M |
|
1303
PUT
Rithm Capital
RITM
$5.09B
| $4.78M | ﹤0.01% |
438,600
-63,100
| -13% | -$697K |
|
1304
Electronic Arts
EA
$52.4B
| $4.78M | ﹤0.01% |
+23,397
| New | +$4.72M |
|
1305
CALL
Edison International
EIX
$30.7B
| $4.78M | ﹤0.01% |
79,600
+4,600
| +6% | +$264K |
|
1306
PUT
Universal Health Services
UHS
$9.43B
| $4.77M | ﹤0.01% |
21,900
-500
| -2% | -$111K |
|
1307
PUT
Joby Aviation
JOBY
$6.96B
| $4.76M | ﹤0.01% |
360,700
-504,900
| -58% | -$7.75M |
|
1308
PUT
SAP
SAP
$188B
| $4.76M | ﹤0.01% |
19,600
-7,000
| -26% | -$1.78M |
|
1309
PUT
Comfort Systems
FIX
$60.2B
| $4.76M | ﹤0.01% |
5,100
+3,400
| +200% | +$3.14M |
|
|
PRMB
1310
Primo Brands
PRMB
$8.24B
| $4.75M | ﹤0.01% |
290,510
+288,052
| +11,719% | +$5.32M |
|
1311
PUT
Canadian Solar
CSIQ
$904M
| $4.75M | ﹤0.01% |
199,800
+98,900
| +98% | +$2.16M |
|
1312
PUT
Western Alliance Bancorporation
WAL
$9.05B
| $4.74M | ﹤0.01% |
56,400
+28,400
| +101% | +$2.31M |
|
1313
Apogee Therapeutics
APGE
$10.2B
| $4.74M | ﹤0.01% |
+62,799
| New | +$3.96M |
|
1314
PUT
BILL Holdings
BILL
$4.34B
| $4.74M | ﹤0.01% |
86,900
-138,300
| -61% | -$7.11M |
|
1315
CALL
Photronics
PLAB
$1.79B
| $4.72M | ﹤0.01% |
147,400
+131,200
| +810% | +$3.38M |
|
1316
Monster Beverage
MNST
$91.3B
| $4.72M | ﹤0.01% |
61,508
+35,525
| +137% | +$2.55M |
|
1317
PUT
Marriott International
MAR
$98.8B
| $4.72M | ﹤0.01% |
15,200
-57,200
| -79% | -$16.3M |
|
1318
PUT
Illumina
ILMN
$29.6B
| $4.71M | ﹤0.01% |
37,400
-9,000
| -19% | -$1.06M |
|
|
SERV
1319
CALL
Serve Robotics
SERV
$419M
| $4.7M | ﹤0.01% |
453,000
-75,500
| -14% | -$907K |
|
1320
Cleveland-Cliffs
CLF
$6.75B
| $4.7M | ﹤0.01% |
353,970
+121,865
| +53% | +$1.54M |
|
1321
CALL
Prudential Financial
PRU
$41.4B
| $4.7M | ﹤0.01% |
41,600
-37,100
| -47% | -$3.98M |
|
1322
CALL
Dutch Bros
BROS
$8.79B
| $4.7M | ﹤0.01% |
76,700
-114,400
| -60% | -$6.5M |
|
1323
CALL
Telephone and Data Systems
TDS
$3.92B
| $4.69M | ﹤0.01% |
114,500
-60,100
| -34% | -$2.34M |
|
1324
CALL
Five Below
FIVE
$11.2B
| $4.69M | ﹤0.01% |
24,900
-11,500
| -32% | -$1.87M |
|
1325
PUT
ArcelorMittal
MT
$50.4B
| $4.69M | ﹤0.01% |
102,900
+1,600
| +2% | +$65.8K |
|
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.