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 | |
|---|---|---|---|---|---|---|
5601
Lincoln Educational Services
LINC
$1.33B
| $53.2K | ﹤0.01% |
2,201
-1,140
| -34% | -$24.8K |
|
5602
Cohu
COHU
$2.26B
| $53.1K | ﹤0.01% |
+2,281
| New | +$52.3K |
|
5603
PUT
Jack in the Box
JACK
$312M
| $53.1K | ﹤0.01% |
2,800
-18,900
| -87% | -$342K |
|
5604
PUT
Adtran
ADTN
$689M
| $53K | ﹤0.01% |
6,100
-4,300
| -41% | -$37.3K |
|
|
RC
5605
PUT
Ready Capital
RC
$258M
| $53K | ﹤0.01% |
24,300
-2,300
| -9% | -$6.44K |
|
|
GAMB
5606
PUT
DELISTED
Gambling.com
GAMB
| $53K | ﹤0.01% |
9,700
-200
| -2% | -$1.27K |
|
5607
PUT
Resideo Technologies
REZI
$5.19B
| $52.7K | ﹤0.01% |
1,500
+1,200
| +400% | +$44.4K |
|
5608
PUT
Loews
L
$23.9B
| $52.7K | ﹤0.01% |
500
+400
| +400% | +$41.3K |
|
|
ODV
5609
DELISTED
Osisko Development Corp
ODV
| $52.6K | ﹤0.01% |
+15,079
| New | +$51.8K |
|
5610
Lands' End
LE
$370M
| $52.6K | ﹤0.01% |
3,624
-2,291
| -39% | -$35.4K |
|
5611
Alto Ingredients
ALTO
$369M
| $52.6K | ﹤0.01% |
18,267
-5,192
| -22% | -$9.79K |
|
5612
CALL
Ethan Allen Interiors
ETD
$570M
| $52.5K | ﹤0.01% |
2,300
-500
| -18% | -$12.5K |
|
|
STEX
5613
CALL
Streamex Corp
STEX
$74M
| $52.4K | ﹤0.01% |
17,300
-12,700
| -42% | -$56.8K |
|
5614
Cato Corp
CATO
$68.3M
| $52.4K | ﹤0.01% |
+16,962
| New | +$62.3K |
|
5615
Alkami Technology
ALKT
$1.94B
| $52.3K | ﹤0.01% |
2,268
-1,923
| -46% | -$42.4K |
|
5616
indie Semiconductor
INDI
$682M
| $52.3K | ﹤0.01% |
+14,808
| New | +$64.9K |
|
|
PENG
5617
Penguin Solutions Inc
PENG
$2.7B
| $52.2K | ﹤0.01% |
+2,671
| New | +$57.2K |
|
5618
PUT
Stepan Co
SCL
$1.46B
| $52.1K | ﹤0.01% |
1,100
-1,800
| -62% | -$82.4K |
|
5619
ProShares Ultra Energy
DIG
$82.8M
| $52.1K | ﹤0.01% |
+1,443
| New | +$51.8K |
|
|
EMPD
5620
Empery Digital
EMPD
$79.8M
| $51.9K | ﹤0.01% |
11,375
+3,463
| +44% | +$20.3K |
|
5621
WisdomTree Artificial Intelligence and Innovation Fund
WTAI
$587M
| $51.8K | ﹤0.01% |
1,776
-1,329
| -43% | -$39.7K |
|
|
TONX
5622
CALL
TON Strategy Co
TONX
$168M
| $51.7K | ﹤0.01% |
26,000
-5,800
| -18% | -$21.2K |
|
5623
PUT
Hexcel
HXL
$7.79B
| $51.7K | ﹤0.01% |
700
+300
| +75% | +$21.2K |
|
5624
Motley Fool 100 Index ETF
TMFC
$2.05B
| $51.7K | ﹤0.01% |
720
+105
| +17% | +$7.5K |
|
5625
CALL
KB Financial Group
KB
$41.4B
| $51.6K | ﹤0.01% |
600
-1,400
| -70% | -$118K |
|
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.