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 | |
|---|---|---|---|---|---|---|
6551
CALL
United States 12 Month Natural Gas Fund
UNL
$13.5M
| $18.4K | ﹤0.01% |
2,500
+1,900
| +317% | +$15.1K |
|
6552
PUT
Fossil Group
FOSL
$293M
| $18.4K | ﹤0.01% |
4,900
-34,500
| -88% | -$97.3K |
|
6553
PUT
Corsair Gaming
CRSR
$1.13B
| $18.4K | ﹤0.01% |
3,100
-2,100
| -40% | -$14.6K |
|
6554
PUT
Baytex Energy
BTE
$3.25B
| $18.4K | ﹤0.01% |
5,700
-12,100
| -68% | -$33.7K |
|
|
HTBK
6555
DELISTED
Heritage Commerce
HTBK
| $18.4K | ﹤0.01% |
1,533
-863
| -36% | -$9.37K |
|
6556
Prothena Corp
PRTA
$425M
| $18.4K | ﹤0.01% |
1,927
-40,117
| -95% | -$408K |
|
6557
iShares Future Exponential Technologies ETF
XT
$3.82B
| $18.3K | ﹤0.01% |
263
+187
| +246% | +$13.7K |
|
6558
Seres Therapeutics
MCRB
$46.8M
| $18.3K | ﹤0.01% |
1,232
-1,575
| -56% | -$27.5K |
|
6559
Suzano
SUZ
$10.5B
| $18.3K | ﹤0.01% |
1,962
-173
| -8% | -$1.57K |
|
6560
PUT
CNB Financial Corp
CCNE
$1.04B
| $18.3K | ﹤0.01% |
700
| – | – |
|
|
TSMY
6561
YieldMax TSM Option Income Strategy ETF
TSMY
$104M
| $18.3K | ﹤0.01% |
1,175
+802
| +215% | +$12.8K |
|
|
PPIH
6562
PUT
Perma-Pipe International
PPIH
$196M
| $18.2K | ﹤0.01% |
600
-4,000
| -87% | -$110K |
|
|
RDNW
6563
CALL
RideNow Group
RDNW
$238M
| $18.2K | ﹤0.01% |
+3,300
| New | +$15.4K |
|
|
IRD
6564
Opus Genetics
IRD
$306M
| $18.2K | ﹤0.01% |
9,063
-23,784
| -72% | -$48.3K |
|
6565
PUT
Apogee Enterprises
APOG
$826M
| $18.2K | ﹤0.01% |
+500
| New | +$18.9K |
|
6566
PUT
Avery Dennison
AVY
$13B
| $18.2K | ﹤0.01% |
100
-400
| -80% | -$69.2K |
|
|
DDL
6567
PUT
Dingdong
DDL
$562M
| $18.2K | ﹤0.01% |
7,300
+4,600
| +170% | +$9.16K |
|
6568
CALL
OraSure Technologies
OSUR
$279M
| $18.1K | ﹤0.01% |
7,500
+7,000
| +1,400% | +$18.4K |
|
6569
CALL
Mineralys Therapeutics
MLYS
$2.25B
| $18.1K | ﹤0.01% |
500
-2,600
| -84% | -$104K |
|
6570
Medallion Financial
MFIN
$229M
| $18.1K | ﹤0.01% |
+1,762
| New | +$17.7K |
|
6571
Frontdoor
FTDR
$5.1B
| $18.1K | ﹤0.01% |
+314
| New | +$18.5K |
|
6572
PUT
Bain Capital Specialty
BCSF
$806M
| $18.1K | ﹤0.01% |
1,300
-5,500
| -81% | -$77.1K |
|
|
TRUE
6573
PUT
DELISTED
TrueCar
TRUE
| $18.1K | ﹤0.01% |
+8,000
| New | +$17.2K |
|
6574
Nkarta
NKTX
$150M
| $18.1K | ﹤0.01% |
9,761
+2,784
| +40% | +$5.57K |
|
6575
CALL
Conduent
CNDT
$244M
| $18K | ﹤0.01% |
9,400
+5,400
| +135% | +$11.8K |
|
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.