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 | |
|---|---|---|---|---|---|---|
1976
PUT
Western Union
WU
$2.57B
| $2.02M | ﹤0.01% |
217,300
+15,000
| +7% | +$132K |
|
|
BTFX
1977
CALL
DELISTED
Valkyrie ETF Trust II CoinShares Bitcoin Leverage ETF
BTFX
| $2.02M | ﹤0.01% |
54,100
+19,800
| +58% | +$869K |
|
1978
PUT
Harmony Gold Mining
HMY
$9.92B
| $2.02M | ﹤0.01% |
101,500
-22,200
| -18% | -$414K |
|
1979
CALL
Skyworks Solutions
SWKS
$9.06B
| $2.02M | ﹤0.01% |
31,800
-1,800
| -5% | -$126K |
|
1980
HDFC Bank
HDB
$119B
| $2.01M | ﹤0.01% |
+55,130
| New | +$1.98M |
|
1981
CALL
GigaCloud Technology
GCT
$1.35B
| $2.01M | ﹤0.01% |
51,100
-28,200
| -36% | -$933K |
|
1982
PennyMac Financial
PFSI
$4.38B
| $2M | ﹤0.01% |
15,151
+6,747
| +80% | +$860K |
|
|
SKE
1983
Skeena Resources
SKE
$3.36B
| $2M | ﹤0.01% |
84,099
+67,582
| +409% | +$1.33M |
|
1984
PUT
Equinix
EQIX
$107B
| $1.99M | ﹤0.01% |
2,600
-3,100
| -54% | -$2.43M |
|
1985
CALL
LegalZoom.com
LZ
$1.23B
| $1.99M | ﹤0.01% |
200,600
-58,600
| -23% | -$581K |
|
1986
PUT
BWX Technologies
BWXT
$16B
| $1.99M | ﹤0.01% |
11,500
-17,800
| -61% | -$3.34M |
|
1987
PUT
Arch Capital
ACGL
$36.1B
| $1.99M | ﹤0.01% |
20,700
+11,800
| +133% | +$1.08M |
|
1988
Birkenstock
BIRK
$7.47B
| $1.98M | ﹤0.01% |
48,446
+19,275
| +66% | +$816K |
|
1989
CALL
Entegris
ENTG
$19.7B
| $1.98M | ﹤0.01% |
23,500
-4,700
| -17% | -$408K |
|
1990
Moog Inc Class A
MOG.A
$13B
| $1.98M | ﹤0.01% |
8,125
+7,401
| +1,022% | +$1.62M |
|
1991
PUT
ChargePoint
CHPT
$133M
| $1.98M | ﹤0.01% |
298,000
-18,100
| -6% | -$171K |
|
1992
PUT
GlobalFoundries
GFS
$29.4B
| $1.97M | ﹤0.01% |
56,500
+6,500
| +13% | +$231K |
|
1993
CALL
Owens Corning
OC
$11.5B
| $1.97M | ﹤0.01% |
17,600
+4,700
| +36% | +$552K |
|
|
FRMI
1994
CALL
Fermi Inc
FRMI
$4.72B
| $1.97M | ﹤0.01% |
+246,200
| New | +$4.8M |
|
1995
PUT
Nutanix
NTNX
$14.9B
| $1.97M | ﹤0.01% |
38,100
-18,400
| -33% | -$1.12M |
|
1996
CALL
Helmerich & Payne
HP
$3.53B
| $1.97M | ﹤0.01% |
68,600
+51,900
| +311% | +$1.38M |
|
1997
PUT
Bath & Body Works
BBWI
$4.01B
| $1.96M | ﹤0.01% |
97,800
-216,200
| -69% | -$4.77M |
|
1998
CALL
Beam Therapeutics
BEAM
$2.58B
| $1.96M | ﹤0.01% |
70,800
+33,400
| +89% | +$852K |
|
|
PONY
1999
PUT
Pony AI Inc
PONY
$3.1B
| $1.96M | ﹤0.01% |
135,200
-217,100
| -62% | -$3.61M |
|
2000
Enova International
ENVA
$5.91B
| $1.96M | ﹤0.01% |
12,470
+6,909
| +124% | +$899K |
|
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.