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 | |
|---|---|---|---|---|---|---|
6301
PUT
Navigator Holdings
NVGS
$1.38B
| $24.2K | ﹤0.01% |
1,400
-1,900
| -58% | -$31.7K |
|
6302
Global X Cybersecurity ETF
BUG
$1.28B
| $24.2K | ﹤0.01% |
795
-15,213
| -95% | -$503K |
|
6303
CALL
BioLife Solutions
BLFS
$1.53B
| $24.2K | ﹤0.01% |
1,000
| – | – |
|
6304
CALL
KBR
KBR
$4.62B
| $24.1K | ﹤0.01% |
600
-1,100
| -65% | -$47.2K |
|
6305
CALL
Assurant
AIZ
$13.8B
| $24.1K | ﹤0.01% |
+100
| New | +$22.3K |
|
6306
PUT
Aemetis
AMTX
$106M
| $24K | ﹤0.01% |
17,300
-33,800
| -66% | -$68K |
|
6307
First Trust Natural Gas ETF
FCG
$647M
| $24K | ﹤0.01% |
1,025
+297
| +41% | +$6.95K |
|
6308
PUT
Innoviva
INVA
$1.55B
| $24K | ﹤0.01% |
1,200
+1,000
| +500% | +$19.5K |
|
6309
PUT
Lincoln Electric
LECO
$14.2B
| $24K | ﹤0.01% |
+100
| New | +$23.7K |
|
6310
CALL
Acushnet Holdings
GOLF
$5.93B
| $23.9K | ﹤0.01% |
+300
| New | +$24.3K |
|
|
BDN
6311
CALL
Brandywine Realty Trust
BDN
$524M
| $23.9K | ﹤0.01% |
8,200
-11,300
| -58% | -$38.4K |
|
6312
PUT
Pliant Therapeutics
PLRX
$64.4M
| $23.9K | ﹤0.01% |
19,600
+13,400
| +216% | +$20.1K |
|
|
BLDP
6313
PUT
Ballard Power Systems
BLDP
$805M
| $23.9K | ﹤0.01% |
9,400
-1,500
| -14% | -$4.65K |
|
6314
CALL
CNA Financial
CNA
$14.2B
| $23.9K | ﹤0.01% |
500
-9,700
| -95% | -$447K |
|
|
VRE
6315
PUT
DELISTED
Veris Residential
VRE
| $23.8K | ﹤0.01% |
+1,600
| New | +$23.6K |
|
|
HTT
6316
CALL
High Templar Tech Ltd
HTT
$379M
| $23.8K | ﹤0.01% |
6,700
-84,200
| -93% | -$376K |
|
6317
CALL
Alpha and Omega Semiconductor
AOSL
$950M
| $23.8K | ﹤0.01% |
1,200
+200
| +20% | +$4.72K |
|
6318
PUT
Century Communities
CCS
$1.91B
| $23.7K | ﹤0.01% |
+400
| New | +$24.3K |
|
6319
CALL
Gray Television
GTN
$415M
| $23.7K | ﹤0.01% |
4,900
-48,800
| -91% | -$239K |
|
6320
CALL
Geospace Technologies
GEOS
$94.6M
| $23.7K | ﹤0.01% |
1,400
-36,300
| -96% | -$729K |
|
6321
VanEck Biotech ETF
BBH
$400M
| $23.7K | ﹤0.01% |
+125
| New | +$23.1K |
|
6322
CALL
Virco
VIRC
$95.2M
| $23.6K | ﹤0.01% |
3,700
-100
| -3% | -$695 |
|
6323
Sensus Healthcare
SRTS
$47.9M
| $23.6K | ﹤0.01% |
5,938
+2,712
| +84% | +$10K |
|
|
NSLR
6324
CALL
Neostellar Capital Corp
NSLR
$269M
| $23.6K | ﹤0.01% |
2,500
-21,700
| -90% | -$204K |
|
6325
PUT
Wolverine World Wide
WWW
$1.61B
| $23.6K | ﹤0.01% |
1,300
-600
| -32% | -$12.1K |
|
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.