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 | |
|---|---|---|---|---|---|---|
4326
CALL
RxSight
RXST
$254M
| $181K | ﹤0.01% |
17,400
+14,700
| +544% | +$148K |
|
4327
PUT
OceanFirst Financial
OCFC
$1.71B
| $181K | ﹤0.01% |
+10,100
| New | +$189K |
|
4328
PUT
Keros Therapeutics
KROS
$197M
| $181K | ﹤0.01% |
8,900
-52,600
| -86% | -$923K |
|
4329
Leonardo DRS
DRS
$12.4B
| $181K | ﹤0.01% |
5,310
-1,544
| -23% | -$57K |
|
4330
CALL
Geron
GERN
$898M
| $181K | ﹤0.01% |
137,000
-76,300
| -36% | -$95.7K |
|
4331
PUT
ODDITY Tech
ODD
$690M
| $181K | ﹤0.01% |
4,500
-9,100
| -67% | -$411K |
|
4332
CALL
Glaukos
GKOS
$9.49B
| $181K | ﹤0.01% |
1,600
-12,100
| -88% | -$1.16M |
|
|
CIM
4333
Chimera Investment
CIM
$1.06B
| $180K | ﹤0.01% |
14,499
-39,641
| -73% | -$504K |
|
4334
loanDepot
LDI
$548M
| $180K | ﹤0.01% |
87,012
+82,417
| +1,794% | +$229K |
|
4335
CALL
GSI Technology
GSIT
$201M
| $180K | ﹤0.01% |
+29,000
| New | +$207K |
|
4336
PUT
Cognex
CGNX
$9.62B
| $180K | ﹤0.01% |
5,000
-1,200
| -19% | -$48.6K |
|
4337
Telus
TU
$17.4B
| $180K | ﹤0.01% |
+13,655
| New | +$192K |
|
4338
CALL
UDR
UDR
$12.9B
| $180K | ﹤0.01% |
4,900
+3,000
| +158% | +$107K |
|
4339
Dyne Therapeutics
DYN
$4.15B
| $180K | ﹤0.01% |
9,186
-5,652
| -38% | -$107K |
|
4340
CALL
NET Power
NPWR
$120M
| $179K | ﹤0.01% |
78,700
-140,500
| -64% | -$439K |
|
4341
Alpha and Omega Semiconductor
AOSL
$829M
| $179K | ﹤0.01% |
9,056
+7,897
| +681% | +$186K |
|
4342
PUT
Nabors Industries
NBR
$1.17B
| $179K | ﹤0.01% |
3,300
-15,100
| -82% | -$736K |
|
4343
USCF Gold Strategy Plus Income Fund
USG
$8.86M
| $179K | ﹤0.01% |
+5,144
| New | +$209K |
|
4344
PUT
Edgewise Therapeutics
EWTX
$4.28B
| $179K | ﹤0.01% |
7,200
+4,100
| +132% | +$82.3K |
|
4345
CALL
Delek Logistics
DKL
$3.12B
| $178K | ﹤0.01% |
4,000
-12,300
| -75% | -$552K |
|
4346
PUT
Sagimet Biosciences
SGMT
$435M
| $178K | ﹤0.01% |
30,100
+13,000
| +76% | +$93.4K |
|
4347
Boston Beer
SAM
$1.95B
| $178K | ﹤0.01% |
911
+372
| +69% | +$76.7K |
|
|
4348
CALL
Sagimet Biosciences
SGMT
$435M
| $178K | ﹤0.01% |
30,000
-21,500
| -42% | -$154K |
|
4349
CALL
China Yuchai International
CYD
$1.69B
| $178K | ﹤0.01% |
5,000
-800
| -14% | -$29.2K |
|
4350
CALL
Vertical Aerospace
EVTL
$154M
| $177K | ﹤0.01% |
33,300
-51,800
| -61% | -$262K |
|
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.