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 | |
|---|---|---|---|---|---|---|
6501
PUT
Dakota Gold
DC
$608M
| $19.3K | ﹤0.01% |
3,400
+800
| +31% | +$3.84K |
|
6502
PUT
Fidus Investment
FDUS
$749M
| $19.3K | ﹤0.01% |
1,000
-100
| -9% | -$1.99K |
|
6503
PUT
Unifirst Corp
UNF
$5.3B
| $19.3K | ﹤0.01% |
+100
| New | +$16.9K |
|
|
STXF
6504
Strive 500 ETF
STXF
$1.12B
| $19.3K | ﹤0.01% |
437
+301
| +221% | +$13.2K |
|
6505
PUT
Mercantile Bank Corp
MBWM
$1.04B
| $19.2K | ﹤0.01% |
400
+200
| +100% | +$9.22K |
|
6506
PUT
Avnet
AVT
$7.29B
| $19.2K | ﹤0.01% |
+400
| New | +$19.7K |
|
6507
CALL
CarGurus
CARG
$3.27B
| $19.2K | ﹤0.01% |
500
-1,200
| -71% | -$43.2K |
|
6508
Paysafe
PSFE
$414M
| $19.2K | ﹤0.01% |
2,368
-2,429
| -51% | -$23.5K |
|
6509
PUT
Monarch Casino & Resort
MCRI
$2.2B
| $19.1K | ﹤0.01% |
+200
| New | +$19.2K |
|
6510
PUT
Ryder
R
$9.83B
| $19.1K | ﹤0.01% |
100
-1,400
| -93% | -$252K |
|
|
PKST
6511
DELISTED
Peakstone Realty Trust
PKST
| $19.1K | ﹤0.01% |
+1,329
| New | +$18.3K |
|
6512
CALL
Choice Hotels
CHH
$5.07B
| $19.1K | ﹤0.01% |
200
-300
| -60% | -$28.6K |
|
6513
PUT
Oportun Financial
OPRT
$255M
| $19K | ﹤0.01% |
+3,600
| New | +$19K |
|
6514
Axcelis
ACLS
$4.01B
| $19K | ﹤0.01% |
237
-18,650
| -99% | -$1.56M |
|
6515
Allot
ALLT
$372M
| $19K | ﹤0.01% |
1,937
-26,203
| -93% | -$251K |
|
6516
CALL
Fuel Tech
FTEK
$43.9M
| $19K | ﹤0.01% |
12,200
-21,300
| -64% | -$46.9K |
|
6517
CALL
StoneX
SNEX
$9.26B
| $19K | ﹤0.01% |
450
| – | – |
|
6518
Pacer Data and Digital Revolution ETF
TRFK
$945M
| $19K | ﹤0.01% |
297
+188
| +172% | +$12.8K |
|
|
BWAY
6519
CALL
Brainsway
BWAY
$611M
| $19K | ﹤0.01% |
2,000
-2,000
| -50% | -$16.5K |
|
6520
iShares MSCI Hong Kong ETF
EWH
$1.24B
| $19K | ﹤0.01% |
+894
| New | +$19.5K |
|
6521
CALL
Abeona Therapeutics
ABEO
$366M
| $19K | ﹤0.01% |
3,600
-5,200
| -59% | -$26.2K |
|
6522
PUT
Erasca
ERAS
$6.3B
| $19K | ﹤0.01% |
5,100
+4,600
| +920% | +$12.9K |
|
6523
CALL
Nurix Therapeutics
NRIX
$2.41B
| $19K | ﹤0.01% |
1,000
-200
| -17% | -$2.87K |
|
6524
Xometry
XMTR
$4.74B
| $19K | ﹤0.01% |
+319
| New | +$18K |
|
6525
CALL
Paymentus
PAY
$4.29B
| $19K | ﹤0.01% |
600
-2,200
| -79% | -$71.8K |
|
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.