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 | Miscellaneous | 98.27% |
| 2 | Technology | 0.59% |
| 3 | Consumer Discretionary | 0.21% |
| 4 | Healthcare | 0.2% |
| 5 | Industrials | 0.18% |
| Name | Market Value | Portfolio Weight | Shares or Principal |
Change in Stake | Capital Flow | |
|---|---|---|---|---|---|---|
1726
PUT
Magnite
MGNI
$3.38B
| $2.74M | ﹤0.01% |
169,100
-15,600
| -8% | -$259K |
|
1727
CALL
Darling Ingredients
DAR
$10.6B
| $2.74M | ﹤0.01% |
76,200
-54,100
| -42% | -$1.83M |
|
1728
CALL
Jazz Pharmaceuticals
JAZZ
$15.7B
| $2.74M | ﹤0.01% |
16,100
-3,000
| -16% | -$460K |
|
1729
PUT
Williams-Sonoma
WSM
$27B
| $2.73M | ﹤0.01% |
15,300
-900
| -6% | -$169K |
|
1730
Mondelez International
MDLZ
$77.7B
| $2.73M | ﹤0.01% |
50,704
+27,726
| +121% | +$1.6M |
|
1731
PUT
Cintas
CTAS
$79.7B
| $2.73M | ﹤0.01% |
14,500
-26,000
| -64% | -$4.9M |
|
1732
CALL
Gartner
IT
$11.1B
| $2.72M | ﹤0.01% |
10,800
+5,400
| +100% | +$1.3M |
|
1733
CALL
Dave Inc
DAVE
$4.8B
| $2.72M | ﹤0.01% |
12,300
-800
| -6% | -$172K |
|
1734
CALL
Applied Optoelectronics
AAOI
$9.83B
| $2.72M | ﹤0.01% |
78,100
-102,100
| -57% | -$3.05M |
|
1735
CALL
KB Home
KBH
$3.12B
| $2.72M | ﹤0.01% |
48,200
-83,500
| -63% | -$5.14M |
|
1736
Waste Management
WM
$86.7B
| $2.72M | ﹤0.01% |
12,363
-3,779
| -23% | -$805K |
|
1737
PUT
American Water Works
AWK
$28B
| $2.71M | ﹤0.01% |
20,800
-2,900
| -12% | -$387K |
|
1738
CALL
BWX Technologies
BWXT
$14.8B
| $2.71M | ﹤0.01% |
15,700
-53,600
| -77% | -$10.1M |
|
|
MESO
1739
CALL
Mesoblast
MESO
$2.15B
| $2.71M | ﹤0.01% |
150,300
+88,400
| +143% | +$1.52M |
|
1740
PUT
Blackstone Mortgage Trust
BXMT
$2.35B
| $2.71M | ﹤0.01% |
141,500
-43,100
| -23% | -$817K |
|
1741
CALL
Baxter International
BAX
$12.8B
| $2.71M | ﹤0.01% |
141,600
-14,200
| -9% | -$284K |
|
1742
CALL
Cognex
CGNX
$10.6B
| $2.69M | ﹤0.01% |
74,900
+10,600
| +16% | +$429K |
|
1743
CALL
Cboe Global Markets
CBOE
$30.6B
| $2.69M | ﹤0.01% |
10,700
+2,100
| +24% | +$522K |
|
|
PR
1744
PUT
Permian Resources
PR
$19.9B
| $2.68M | ﹤0.01% |
190,900
-11,500
| -6% | -$154K |
|
|
1745
CALL
American Water Works
AWK
$28B
| $2.68M | ﹤0.01% |
20,500
+2,300
| +13% | +$307K |
|
1746
CALL
Public Storage
PSA
$55.6B
| $2.67M | ﹤0.01% |
10,300
-2,600
| -20% | -$728K |
|
1747
CALL
Xponential Fitness
XPOF
$205M
| $2.67M | ﹤0.01% |
324,700
-54,800
| -14% | -$389K |
|
1748
CALL
ICICI Bank
IBN
$106B
| $2.67M | ﹤0.01% |
89,600
-77,600
| -46% | -$2.38M |
|
1749
PUT
GeneDx Holdings
WGS
$2.52B
| $2.67M | ﹤0.01% |
20,500
-25,200
| -55% | -$3.46M |
|
1750
CALL
Kinetik
KNTK
$4.45B
| $2.66M | ﹤0.01% |
73,900
+25,600
| +53% | +$925K |
|
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's Q4 2025 filing shows 1,476 new, 2,599 increased, 4,088 reduced and 2,184 closed positions. Its largest new stake was Western Digital: 341,762 shares worth $58.9M. The largest sale was NVIDIA, an estimated $262M.
By sector, the portfolio is most concentrated in Miscellaneous at 98% of assets, up from 98% a quarter earlier, followed by Technology and Consumer Discretionary.
- 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.