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 | |
|---|---|---|---|---|---|---|
5426
Trinity Industries
TRN
$2.49B
| $64.1K | ﹤0.01% |
+2,425
| New | +$65.9K |
|
5427
CALL
Energy Vault
NRGV
$517M
| $64.1K | ﹤0.01% |
13,900
+6,900
| +99% | +$26.4K |
|
|
MAGC
5428
Roundhill China Magnificent Seven ETF
MAGC
$14.7M
| $64K | ﹤0.01% |
2,691
-5,041
| -65% | -$132K |
|
5429
CALL
Stereotaxis
STXS
$126M
| $63.9K | ﹤0.01% |
27,800
-1,200
| -4% | -$3.19K |
|
|
PLG
5430
Platinum Group Metals
PLG
$164M
| $63.9K | ﹤0.01% |
27,089
-90,534
| -77% | -$219K |
|
5431
CALL
Talkspace
TALK
$874M
| $63.9K | ﹤0.01% |
17,600
+8,200
| +87% | +$26K |
|
5432
PUT
TPG
TPG
$7.01B
| $63.8K | ﹤0.01% |
1,000
-1,900
| -66% | -$112K |
|
5433
CALL
Golub Capital BDC
GBDC
$3.34B
| $63.8K | ﹤0.01% |
4,700
-600
| -11% | -$8.31K |
|
5434
CALL
NETGEAR
NTGR
$648M
| $63.8K | ﹤0.01% |
2,600
-10,300
| -80% | -$296K |
|
5435
CALL
InfuSystem Holdings
INFU
$184M
| $63.7K | ﹤0.01% |
7,100
+5,500
| +344% | +$52.6K |
|
5436
CALL
Puma Biotechnology
PBYI
$404M
| $63.7K | ﹤0.01% |
10,700
-6,500
| -38% | -$34.5K |
|
5437
PUT
Liquidity Services
LQDT
$1.22B
| $63.7K | ﹤0.01% |
2,100
+2,000
| +2,000% | +$53.7K |
|
5438
PUT
SkyWater Technology
SKYT
| $63.6K | ﹤0.01% |
3,500
-4,800
| -58% | -$83.4K |
|
5439
Treace Medical Concepts
TMCI
$280M
| $63.5K | ﹤0.01% |
+25,929
| New | +$113K |
|
5440
PUT
Masco
MAS
$14.1B
| $63.5K | ﹤0.01% |
1,000
-4,800
| -83% | -$311K |
|
5441
PUT
Solventum
SOLV
$14.8B
| $63.4K | ﹤0.01% |
800
-2,400
| -75% | -$184K |
|
|
FJET
5442
Starfighters Space Inc
FJET
$195M
| $63.3K | ﹤0.01% |
+5,435
| New | +$75.1K |
|
|
ZH
5443
CALL
Zhihu
ZH
$281M
| $63.3K | ﹤0.01% |
19,300
-20,600
| -52% | -$82.5K |
|
5444
Clarivate
CLVT
$1.27B
| $63.2K | ﹤0.01% |
18,937
-3,641
| -16% | -$12.9K |
|
5445
Boston Omaha
BOC
$428M
| $63.1K | ﹤0.01% |
5,102
+223
| +5% | +$2.9K |
|
5446
Columbus McKinnon
CMCO
$553M
| $63.1K | ﹤0.01% |
3,656
+2,113
| +137% | +$33.9K |
|
5447
PUT
Neonode
NEON
$14.1M
| $63K | ﹤0.01% |
36,200
-76,200
| -68% | -$202K |
|
5448
CALL
iShares 0-5 Year Investment Grade Corporate Bond ETF
SLQD
$2.37B
| $62.9K | ﹤0.01% |
900
-300
| -25% | -$15.2K |
|
5449
Global X Hydrogen ETF
HYDR
$83.9M
| $62.8K | ﹤0.01% |
1,977
+1,885
| +2,049% | +$73.7K |
|
5450
PUT
Oshkosh
OSK
$8.79B
| $62.8K | ﹤0.01% |
500
+400
| +400% | +$51.4K |
|
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.