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 | |
|---|---|---|---|---|---|---|
5276
Helios Technologies
HLIO
$2.57B
| $75.1K | ﹤0.01% |
+1,404
| New | +$75.7K |
|
5277
CALL
AXIS Capital
AXS
$7.68B
| $75K | ﹤0.01% |
+700
| New | +$69.5K |
|
5278
PUT
Merchants Bancorp
MBIN
$2.53B
| $74.9K | ﹤0.01% |
2,200
+500
| +29% | +$16.4K |
|
|
EHAB
5279
DELISTED
Enhabit
EHAB
| $74.8K | ﹤0.01% |
8,115
+3,336
| +70% | +$28.9K |
|
5280
PUT
Loar Holdings
LOAR
$6.41B
| $74.8K | ﹤0.01% |
1,100
-1,600
| -59% | -$117K |
|
5281
CALL
Materion
MTRN
$4.39B
| $74.6K | ﹤0.01% |
600
+200
| +50% | +$24.7K |
|
|
ASMG
5282
Leverage Shares 2X Long ASML Daily ETF
ASMG
$35.4M
| $74.6K | ﹤0.01% |
3,301
-230
| -7% | -$5.65K |
|
5283
Jackson Financial
JXN
$8.53B
| $74.5K | ﹤0.01% |
+699
| New | +$69.5K |
|
5284
PUT
Rapid7
RPD
$645M
| $74.5K | ﹤0.01% |
4,900
-63,300
| -93% | -$1.04M |
|
5285
PUT
Appian
APPN
$1.98B
| $74.4K | ﹤0.01% |
2,100
-35,000
| -94% | -$1.25M |
|
5286
Verra Mobility
VRRM
$804M
| $74.2K | ﹤0.01% |
3,313
-12,362
| -79% | -$282K |
|
5287
Sprott Junior Uranium Miners ETF
URNJ
$313M
| $74.2K | ﹤0.01% |
+2,946
| New | +$81.1K |
|
5288
CALL
Pacer Trendpilot US Large Cap ETF
PTLC
$3.26B
| $74.2K | ﹤0.01% |
1,700
-8,800
| -84% | -$489K |
|
5289
Sasol
SSL
$7.5B
| $73.9K | ﹤0.01% |
11,352
+5,808
| +105% | +$36.7K |
|
|
ALMU
5290
PUT
Aeluma Inc
ALMU
$297M
| $73.8K | ﹤0.01% |
4,300
+200
| +5% | +$3.16K |
|
|
IRBT
5291
CALL
DELISTED
iRobot
IRBT
| $73.6K | ﹤0.01% |
669,400
+379,600
| +131% | +$1.14M |
|
5292
Satellogic
SATL
$531M
| $73.5K | ﹤0.01% |
39,280
+5,301
| +16% | +$11.5K |
|
5293
CALL
Star Group
SGU
$412M
| $73.4K | ﹤0.01% |
6,200
-1,900
| -23% | -$22.5K |
|
5294
CALL
EnerSys
ENS
$6.78B
| $73.4K | ﹤0.01% |
500
| – | – |
|
5295
PUT
Kontoor Brands
KTB
$4.63B
| $73.3K | ﹤0.01% |
+1,200
| New | +$89.1K |
|
5296
CALL
Rogers Corp
ROG
$2.21B
| $73.3K | ﹤0.01% |
+800
| New | +$68.7K |
|
5297
Vitesse Energy
VTS
$651M
| $73.2K | ﹤0.01% |
3,803
+760
| +25% | +$16.2K |
|
5298
PUT
Lantheus
LNTH
$6.49B
| $73.2K | ﹤0.01% |
1,100
-3,100
| -74% | -$180K |
|
5299
Douglas Dynamics
PLOW
$1.02B
| $73.2K | ﹤0.01% |
+2,241
| New | +$70.9K |
|
5300
CALL
MeiraGTx Holdings
MGTX
$1.09B
| $73.1K | ﹤0.01% |
9,200
+3,400
| +59% | +$28.3K |
|
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.