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 | |
|---|---|---|---|---|---|---|
4951
Archrock
AROC
$6.28B
| $104K | ﹤0.01% |
4,004
-477
| -11% | -$11.9K |
|
4952
Avantor
AVTR
$9.37B
| $104K | ﹤0.01% |
9,091
-20,218
| -69% | -$249K |
|
4953
CALL
Acadia Pharmaceuticals
ACAD
$4.42B
| $104K | ﹤0.01% |
3,900
-17,800
| -82% | -$425K |
|
4954
CALL
AirSculpt Technologies
AIRS
$333M
| $104K | ﹤0.01% |
52,600
+11,300
| +27% | +$68.6K |
|
4955
Main Street Capital
MAIN
$5.08B
| $104K | ﹤0.01% |
+1,723
| New | +$102K |
|
4956
CALL
Corporacion America
CAAP
$4.23B
| $104K | ﹤0.01% |
4,000
+1,400
| +54% | +$31.4K |
|
4957
PUT
Core & Main
CNM
$8.24B
| $104K | ﹤0.01% |
2,000
-34,100
| -94% | -$1.75M |
|
4958
Viant Technology
DSP
$236M
| $104K | ﹤0.01% |
+8,632
| New | +$86.3K |
|
4959
PUT
GrafTech
EAF
$174M
| $104K | ﹤0.01% |
6,700
-4,400
| -40% | -$66.9K |
|
4960
PUT
Invesco CurrencyShares British Pound Sterling Trust
FXB
$77.8M
| $104K | ﹤0.01% |
800
+600
| +300% | +$76.7K |
|
4961
PUT
Danaos Corp
DAC
$2.57B
| $104K | ﹤0.01% |
1,100
-5,900
| -84% | -$544K |
|
4962
Repay Holdings
RPAY
$331M
| $104K | ﹤0.01% |
28,374
-14,226
| -33% | -$57K |
|
4963
AAR Corp
AIR
$5.6B
| $103K | ﹤0.01% |
1,250
-19,957
| -94% | -$1.65M |
|
4964
PUT
Snap-on
SNA
$21.3B
| $103K | ﹤0.01% |
300
| – | – |
|
|
BRSL
4965
Brightstar Lottery PLC
BRSL
$1.84B
| $103K | ﹤0.01% |
6,663
-2,715
| -29% | -$44.2K |
|
|
ORBS
4966
PUT
Eightco Holdings
ORBS
$234M
| $103K | ﹤0.01% |
+59,600
| New | +$280K |
|
4967
PUT
LGI Homes
LGIH
$1.27B
| $103K | ﹤0.01% |
2,400
+2,300
| +2,300% | +$108K |
|
4968
CALL
Astronics
ATRO
$3.43B
| $103K | ﹤0.01% |
2,280
-6,240
| -73% | -$262K |
|
4969
CALL
WesBanco
WSBC
$3.97B
| $103K | ﹤0.01% |
3,100
-2,100
| -40% | -$67.9K |
|
4970
CALL
Genpact
G
$5.95B
| $103K | ﹤0.01% |
2,200
-2,200
| -50% | -$95.1K |
|
4971
PUT
TransUnion
TRU
$15.1B
| $103K | ﹤0.01% |
1,200
-5,800
| -83% | -$477K |
|
|
NPKI
4972
NPK International
NPKI
$1.06B
| $103K | ﹤0.01% |
+8,629
| New | +$105K |
|
|
SUNS
4973
CALL
Sunrise Realty Trust
SUNS
$106M
| $103K | ﹤0.01% |
10,900
-300
| -3% | -$2.94K |
|
4974
PUT
Stellus Capital Investment Corp
SCM
$216M
| $103K | ﹤0.01% |
8,100
+4,700
| +138% | +$57.6K |
|
|
LIF
4975
PUT
Life360
LIF
$4.39B
| $103K | ﹤0.01% |
1,600
+1,400
| +700% | +$116K |
|
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.