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 | |
|---|---|---|---|---|---|---|
2476
CALL
Royalty Pharma
RPRX
$26.1B
| $1.17M | ﹤0.01% |
30,200
-51,700
| -63% | -$1.97M |
|
2477
Rollins
ROL
$18.6B
| $1.17M | ﹤0.01% |
19,431
+18,343
| +1,686% | +$1.08M |
|
2478
CALL
Icon
ICLR
$12.8B
| $1.17M | ﹤0.01% |
6,400
+4,900
| +327% | +$873K |
|
2479
PUT
Corebridge Financial
CRBG
$14.1B
| $1.16M | ﹤0.01% |
38,600
+21,100
| +121% | +$649K |
|
2480
CALL
Sterling Infrastructure
STRL
$20.3B
| $1.16M | ﹤0.01% |
3,800
-2,600
| -41% | -$896K |
|
2481
CALL
Casey's General Stores
CASY
$31.9B
| $1.16M | ﹤0.01% |
2,100
+1,700
| +425% | +$936K |
|
2482
CALL
Argan
AGX
$7.98B
| $1.16M | ﹤0.01% |
3,700
+800
| +28% | +$254K |
|
2483
Ferrari
RACE
$63.3B
| $1.16M | ﹤0.01% |
+3,136
| New | +$1.25M |
|
2484
Varonis Systems
VRNS
$5.25B
| $1.16M | ﹤0.01% |
35,326
+18,812
| +114% | +$790K |
|
|
EH
2485
PUT
EHang Holdings
EH
$372M
| $1.16M | ﹤0.01% |
87,900
-303,500
| -78% | -$4.79M |
|
2486
PUT
Ferguson
FERG
$44.7B
| $1.16M | ﹤0.01% |
5,200
-3,300
| -39% | -$788K |
|
2487
TETRA Technologies
TTI
$1.23B
| $1.16M | ﹤0.01% |
+123,456
| New | +$953K |
|
2488
CALL
IDEX
IEX
$16.5B
| $1.16M | ﹤0.01% |
+6,500
| New | +$1.11M |
|
|
CTLP
2489
PUT
DELISTED
Cantaloupe
CTLP
| $1.16M | ﹤0.01% |
108,900
+64,400
| +145% | +$683K |
|
2490
PUT
Spyre Therapeutics
SYRE
$8.87B
| $1.16M | ﹤0.01% |
+35,300
| New | +$922K |
|
|
DFTX
2491
CALL
Definium Therapeutics
DFTX
$5.73B
| $1.16M | ﹤0.01% |
86,300
-23,000
| -21% | -$285K |
|
2492
CALL
Burlington
BURL
$22B
| $1.16M | ﹤0.01% |
4,000
-14,600
| -78% | -$3.96M |
|
|
CDTX
2493
DELISTED
Cidara Therapeutics
CDTX
| $1.16M | ﹤0.01% |
5,230
-7,897
| -60% | -$1.28M |
|
2494
Nutrien
NTR
$32.7B
| $1.15M | ﹤0.01% |
18,681
+16,250
| +668% | +$956K |
|
2495
PUT
Monte Rosa Therapeutics
GLUE
$1.92B
| $1.15M | ﹤0.01% |
73,500
-85,600
| -54% | -$1.15M |
|
2496
PUT
Vanguard S&P 500 Growth ETF
VOOG
$25.4B
| $1.15M | ﹤0.01% |
16,200
+12,000
| +286% | +$883K |
|
|
LAC
2497
PUT
Lithium Americas
LAC
$986M
| $1.15M | ﹤0.01% |
263,800
-385,700
| -59% | -$2.23M |
|
2498
PUT
Yum! Brands
YUM
$41B
| $1.15M | ﹤0.01% |
7,600
-11,500
| -60% | -$1.7M |
|
2499
CALL
AbCellera Biologics
ABCL
$1.62B
| $1.15M | ﹤0.01% |
336,100
+17,400
| +5% | +$77.7K |
|
|
MDLN
2500
Medline Inc
MDLN
$32.8B
| $1.15M | ﹤0.01% |
+27,297
| New | +$1.15M |
|
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.