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 | |
|---|---|---|---|---|---|---|
|
MBX
2276
PUT
MBX Biosciences
MBX
$2.95B
| $1.41M | ﹤0.01% |
44,700
-97,200
| -68% | -$2.36M |
|
2277
BridgeBio Pharma
BBIO
$16.5B
| $1.41M | ﹤0.01% |
+18,412
| New | +$1.21M |
|
2278
CALL
Illinois Tool Works
ITW
$81.4B
| $1.4M | ﹤0.01% |
5,700
-56,200
| -91% | -$14M |
|
|
JKS
2279
PUT
JinkoSolar
JKS
$775M
| $1.4M | ﹤0.01% |
54,300
-5,300
| -9% | -$135K |
|
2280
PUT
CoStar Group
CSGP
$11.3B
| $1.4M | ﹤0.01% |
57,700
-5,300
| -8% | -$375K |
|
|
FINV
2281
CALL
FinVolution Group
FINV
$1.12B
| $1.4M | ﹤0.01% |
267,800
+251,800
| +1,574% | +$1.48M |
|
2282
PUT
Gen Digital
GEN
$15.6B
| $1.4M | ﹤0.01% |
+51,500
| New | +$1.39M |
|
2283
Direxion Daily GOOGL Bull 2X ETF
GGLL
$835M
| $1.4M | ﹤0.01% |
14,428
-1,812
| -11% | -$154K |
|
|
NGD
2284
CALL
DELISTED
New Gold Inc
NGD
| $1.4M | ﹤0.01% |
160,400
-604,700
| -79% | -$4.55M |
|
2285
PUT
Huntington Ingalls Industries
HII
$11.3B
| $1.39M | ﹤0.01% |
4,100
-1,300
| -24% | -$403K |
|
2286
PUT
Boot Barn
BOOT
$4.55B
| $1.39M | ﹤0.01% |
7,900
+2,100
| +36% | +$392K |
|
2287
PUT
TTM Technologies
TTMI
$13.6B
| $1.39M | ﹤0.01% |
20,200
-98,200
| -83% | -$6.41M |
|
2288
PUT
Eversource Energy
ES
$28.2B
| $1.39M | ﹤0.01% |
20,700
-6,900
| -25% | -$484K |
|
|
NNDM
2289
Nano Dimension
NNDM
$309M
| $1.39M | ﹤0.01% |
903,900
-54,823
| -6% | -$92.9K |
|
2290
PUT
Ero Copper
ERO
$2.71B
| $1.39M | ﹤0.01% |
49,200
+10,700
| +28% | +$249K |
|
2291
PUT
UroGen Pharma
URGN
$2B
| $1.39M | ﹤0.01% |
59,400
+10,100
| +20% | +$219K |
|
2292
PUT
Levi Strauss
LEVI
$9.44B
| $1.39M | ﹤0.01% |
66,900
-99,600
| -60% | -$2.15M |
|
2293
CALL
Elanco Animal Health
ELAN
$12.4B
| $1.39M | ﹤0.01% |
61,300
-19,100
| -24% | -$416K |
|
2294
CALL
Entergy
ETR
$54.1B
| $1.39M | ﹤0.01% |
15,000
-7,800
| -34% | -$740K |
|
2295
PUT
Darling Ingredients
DAR
$9.93B
| $1.38M | ﹤0.01% |
38,400
-30,300
| -44% | -$1.03M |
|
2296
CALL
Fulgent Genetics
FLGT
$559M
| $1.38M | ﹤0.01% |
52,600
-112,400
| -68% | -$2.92M |
|
2297
CALL
Iridium Communications
IRDM
$4.85B
| $1.38M | ﹤0.01% |
79,500
+56,200
| +241% | +$993K |
|
2298
CALL
Mattel
MAT
$4.17B
| $1.38M | ﹤0.01% |
69,600
+28,700
| +70% | +$554K |
|
2299
PUT
Unilever
UL
$131B
| $1.38M | ﹤0.01% |
104,100
+2,856
| +3% | +$192K |
|
2300
State Street
STT
$50.9B
| $1.38M | ﹤0.01% |
+10,683
| New | +$1.28M |
|
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.