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 | |
|---|---|---|---|---|---|---|
5251
ProShares UltraShort Real Estate
SRS
$15.3M
| $77.8K | ﹤0.01% |
1,577
-4
| -0.3% | -$193 |
|
5252
PUT
IES Holdings
IESC
$14.8B
| $77.8K | ﹤0.01% |
200
-900
| -82% | -$362K |
|
5253
Oceaneering
OII
$4.86B
| $77.8K | ﹤0.01% |
3,237
+3,136
| +3,105% | +$75.7K |
|
5254
CALL
Park Hotels & Resorts
PK
$3.03B
| $77.4K | ﹤0.01% |
7,400
-30,000
| -80% | -$321K |
|
5255
PUT
Ibotta
IBTA
$559M
| $77.3K | ﹤0.01% |
3,400
+200
| +6% | +$5.4K |
|
5256
PUT
Savara
SVRA
$1.12B
| $77.2K | ﹤0.01% |
12,800
+1,500
| +13% | +$7.35K |
|
5257
nVent Electric
NVT
$24.9B
| $76.9K | ﹤0.01% |
+754
| New | +$78.3K |
|
5258
CALL
Arch Capital
ACGL
$34.3B
| $76.7K | ﹤0.01% |
800
-12,200
| -94% | -$1.12M |
|
|
TGNA
5259
DELISTED
TEGNA Inc
TGNA
| $76.7K | ﹤0.01% |
3,950
-55,609
| -93% | -$1.1M |
|
|
BLCN
5260
CALL
DELISTED
Siren ETF Trust Siren NexGen Economy ETF
BLCN
| $76.6K | ﹤0.01% |
3,200
| – | – |
|
5261
PUT
OSI Systems
OSIS
$3.65B
| $76.5K | ﹤0.01% |
300
-100
| -25% | -$26.1K |
|
5262
Churchill Downs
CHDN
$5.88B
| $76.3K | ﹤0.01% |
671
-2,751
| -80% | -$285K |
|
5263
Pulmonx
LUNG
$68.8M
| $76.3K | ﹤0.01% |
34,518
-4,621
| -12% | -$8.69K |
|
5264
CALL
First Interstate BancSystem
FIBK
$3.69B
| $76.1K | ﹤0.01% |
2,200
-4,600
| -68% | -$151K |
|
5265
PUT
Insteel Industries
IIIN
$593M
| $76K | ﹤0.01% |
+2,400
| New | +$78.3K |
|
5266
PUT
California Resources
CRC
$4.67B
| $76K | ﹤0.01% |
1,700
-2,500
| -60% | -$119K |
|
|
TGR
5267
CALL
DELISTED
ISHARES TARGET DATE RETIREMENT INCOME ETF
TGR
| $75.9K | ﹤0.01% |
1,400
-900
| -39% | -$48.8K |
|
5268
PUT
ARKO Corp
ARKO
$896M
| $75.8K | ﹤0.01% |
16,700
+2,600
| +18% | +$11.7K |
|
5269
CALL
Myriad Genetics
MYGN
$270M
| $75.6K | ﹤0.01% |
12,300
-700
| -5% | -$5.08K |
|
5270
PUT
Tecnoglass Holdings Inc.
TGLS
$1.93B
| $75.5K | ﹤0.01% |
1,500
-2,300
| -61% | -$126K |
|
5271
PUT
Vanguard Total International Stock ETF
VXUS
$155B
| $75.4K | ﹤0.01% |
1,000
-5,800
| -85% | -$433K |
|
5272
Jakks Pacific
JAKK
$301M
| $75.4K | ﹤0.01% |
4,464
+838
| +23% | +$14.5K |
|
|
MRUS
5273
DELISTED
Merus
MRUS
| $75.3K | ﹤0.01% |
+837
| New | +$79.9K |
|
5274
CALL
NatWest
NWG
$75.4B
| $75.3K | ﹤0.01% |
4,300
-36,000
| -89% | -$571K |
|
5275
PUT
Gates Industrial Corporation Ltd.
GTES
$7.08B
| $75.1K | ﹤0.01% |
3,500
+200
| +6% | +$4.62K |
|
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.