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 | |
|---|---|---|---|---|---|---|
2301
Markel Group
MKL
$25B
| $1.38M | ﹤0.01% |
640
+590
| +1,180% | +$1.2M |
|
2302
PUT
Return Stacked Bonds & Managed Futures ETF
RSBT
$137M
| $1.38M | ﹤0.01% |
254,000
-829,500
| -77% | -$15M |
|
2303
CALL
Progress Software
PRGS
$1.55B
| $1.37M | ﹤0.01% |
32,000
-51,100
| -61% | -$2.23M |
|
2304
CALL
Liberty Global Class C
LBTYK
$3.27B
| $1.37M | ﹤0.01% |
123,400
+105,200
| +578% | +$1.17M |
|
|
CCCX
2305
CALL
DELISTED
Churchill Capital Corp X
CCCX
| $1.37M | ﹤0.01% |
88,100
+83,900
| +1,998% | +$1.41M |
|
|
GRAL
2306
GRAIL Inc
GRAL
$2.91B
| $1.37M | ﹤0.01% |
+16,051
| New | +$1.39M |
|
2307
Navitas Semiconductor
NVTS
$2.66B
| $1.37M | ﹤0.01% |
192,250
+6,317
| +3% | +$60.8K |
|
2308
CALL
Gevo
GEVO
$396M
| $1.37M | ﹤0.01% |
685,100
+644,000
| +1,567% | +$1.42M |
|
|
FETH
2309
Fidelity Ethereum Fund
FETH
$1B
| $1.37M | ﹤0.01% |
+46,246
| New | +$1.6M |
|
|
MRUS
2310
CALL
DELISTED
Merus
MRUS
| $1.37M | ﹤0.01% |
15,200
-43,200
| -74% | -$4.12M |
|
2311
CALL
Dover
DOV
$27.2B
| $1.37M | ﹤0.01% |
7,000
-7,100
| -50% | -$1.29M |
|
2312
United Natural Foods
UNFI
$3.01B
| $1.37M | ﹤0.01% |
40,580
-34,247
| -46% | -$1.27M |
|
2313
Cintas
CTAS
$82.4B
| $1.37M | ﹤0.01% |
7,264
-641
| -8% | -$121K |
|
2314
CALL
Rayonier Advanced Materials
RYAM
$565M
| $1.37M | ﹤0.01% |
231,800
+227,200
| +4,939% | +$1.48M |
|
2315
CALL
Millicom
TIGO
$15.8B
| $1.36M | ﹤0.01% |
24,600
+4,900
| +25% | +$247K |
|
2316
CoreCivic
CXW
$3.1B
| $1.36M | ﹤0.01% |
71,322
+14,578
| +26% | +$267K |
|
2317
Icahn Enterprises
IEP
$5.17B
| $1.36M | ﹤0.01% |
180,506
+145,642
| +418% | +$1.17M |
|
2318
CALL
JB Hunt Transport Services
JBHT
$27.1B
| $1.36M | ﹤0.01% |
7,000
-6,100
| -47% | -$1.05M |
|
2319
CALL
Huntington Ingalls Industries
HII
$11.3B
| $1.36M | ﹤0.01% |
4,000
-5,800
| -59% | -$1.8M |
|
2320
CALL
Altimmune
ALT
$539M
| $1.36M | ﹤0.01% |
376,800
+63,400
| +20% | +$276K |
|
2321
PUT
XPO
XPO
$25B
| $1.36M | ﹤0.01% |
10,000
-7,200
| -42% | -$981K |
|
2322
CALL
Amplify Energy
AMPY
$163M
| $1.36M | ﹤0.01% |
297,200
-246,000
| -45% | -$1.22M |
|
2323
EnerSys
ENS
$6.95B
| $1.36M | ﹤0.01% |
9,252
+4,074
| +79% | +$544K |
|
2324
PUT
Perion Network
PERI
$367M
| $1.35M | ﹤0.01% |
141,400
-42,700
| -23% | -$415K |
|
2325
PUT
DigitalBridge
DBRG
$2.94B
| $1.35M | ﹤0.01% |
88,100
-23,600
| -21% | -$284K |
|
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.