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 | |
|---|---|---|---|---|---|---|
2176
PUT
Parker-Hannifin
PH
$125B
| $1.58M | ﹤0.01% |
1,800
-900
| -33% | -$737K |
|
2177
PUT
Zions Bancorporation
ZION
$10.1B
| $1.58M | ﹤0.01% |
27,000
-5,400
| -17% | -$294K |
|
2178
Cummins
CMI
$91.7B
| $1.58M | ﹤0.01% |
3,093
+2,566
| +487% | +$1.2M |
|
2179
CALL
Par Pacific Holdings
PARR
$3.88B
| $1.58M | ﹤0.01% |
44,900
+300
| +0.7% | +$11.9K |
|
2180
CALL
Alphatec Holdings
ATEC
$1.27B
| $1.58M | ﹤0.01% |
74,900
-40,900
| -35% | -$757K |
|
2181
PUT
Burford Capital
BUR
$907M
| $1.57M | ﹤0.01% |
176,400
+33,400
| +23% | +$327K |
|
|
KNGS
2182
PUT
DELISTED
Roundhill S&P Dividend Monarchs ETF
KNGS
| $1.57M | ﹤0.01% |
47,700
+7,100
| +17% | +$234K |
|
2183
CALL
Hycroft Mining Holding Corp
HYMC
$1.85B
| $1.57M | ﹤0.01% |
66,100
-72,000
| -52% | -$797K |
|
2184
Lionsgate Studios
LION
$3.88B
| $1.56M | ﹤0.01% |
171,028
+169,548
| +11,456% | +$1.21M |
|
2185
CALL
WIX.com
WIX
$2.15B
| $1.56M | ﹤0.01% |
15,000
-17,200
| -53% | -$2.08M |
|
2186
PUT
Jackson Financial
JXN
$8.32B
| $1.56M | ﹤0.01% |
14,600
-11,400
| -44% | -$1.13M |
|
2187
Harley-Davidson
HOG
$2.68B
| $1.56M | ﹤0.01% |
75,979
-64,459
| -46% | -$1.58M |
|
|
MFA
2188
PUT
MFA Financial
MFA
$929M
| $1.55M | ﹤0.01% |
167,000
+27,300
| +20% | +$254K |
|
2189
CALL
XP
XP
$8.62B
| $1.55M | ﹤0.01% |
94,800
+60,400
| +176% | +$1.06M |
|
2190
PUT
FIVE9
FIVN
$1.77B
| $1.55M | ﹤0.01% |
77,300
-6,200
| -7% | -$132K |
|
2191
PUT
MSCI
MSCI
$40B
| $1.55M | ﹤0.01% |
2,700
-5,700
| -68% | -$3.2M |
|
|
UROY
2192
CALL
Uranium Royalty Corp
UROY
$434M
| $1.55M | ﹤0.01% |
436,700
+430,900
| +7,429% | +$1.69M |
|
2193
CALL
NewAmsterdam Pharma
NAMS
$3.47B
| $1.54M | ﹤0.01% |
44,000
+43,700
| +14,567% | +$1.59M |
|
|
STUB
2194
PUT
StubHub Holdings
STUB
$3.1B
| $1.54M | ﹤0.01% |
113,900
+27,300
| +32% | +$429K |
|
2195
PUT
BorgWarner
BWA
$13.2B
| $1.54M | ﹤0.01% |
34,200
-81,900
| -71% | -$3.59M |
|
2196
CALL
Organon & Co
OGN
$3.55B
| $1.54M | ﹤0.01% |
214,900
+110,400
| +106% | +$872K |
|
2197
Blackrock
BLK
$164B
| $1.54M | ﹤0.01% |
+1,439
| New | +$1.57M |
|
2198
PUT
GigaCloud Technology
GCT
$1.35B
| $1.54M | ﹤0.01% |
39,200
-5,900
| -13% | -$195K |
|
2199
CALL
Invitation Homes
INVH
$17.7B
| $1.54M | ﹤0.01% |
55,400
-99,200
| -64% | -$2.77M |
|
2200
PUT
Carbon Collective Climate Solutions US Equity ETF
CCSO
$45.3M
| $1.54M | ﹤0.01% |
106,200
-360,900
| -77% | -$9.06M |
|
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.