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 | |
|---|---|---|---|---|---|---|
6576
Strategic Education
STRA
$1.85B
| $18K | ﹤0.01% |
+225
| New | +$18K |
|
6577
PUT
OneSpan
OSPN
$574M
| $18K | ﹤0.01% |
1,400
+900
| +180% | +$12.2K |
|
6578
PUT
The RMR Group
RMR
$325M
| $17.9K | ﹤0.01% |
1,200
+700
| +140% | +$10.7K |
|
6579
PUT
Runway Growth Finance
RWAY
$232M
| $17.9K | ﹤0.01% |
+2,000
| New | +$19K |
|
|
IRE
6580
Defiance Daily Target 2x Long IREN ETF
IRE
$212M
| $17.8K | ﹤0.01% |
+751
| New | +$38.1K |
|
6581
CBIZ
CBZ
$2.99B
| $17.8K | ﹤0.01% |
+353
| New | +$18.6K |
|
6582
PUT
Phillips Edison & Co
PECO
$5.46B
| $17.8K | ﹤0.01% |
500
-200
| -29% | -$6.94K |
|
|
GRFS
6583
PUT
Grifois
GRFS
$5.36B
| $17.8K | ﹤0.01% |
1,900
-8,200
| -81% | -$74.6K |
|
|
MIAX
6584
CALL
Miami International Holdings
MIAX
$4.55B
| $17.8K | ﹤0.01% |
400
-41,700
| -99% | -$1.86M |
|
|
HIMZ
6585
Defiance Daily Target 2X Long HIMS ETF
HIMZ
$60.1M
| $17.7K | ﹤0.01% |
+218
| New | +$36.4K |
|
6586
First Trust Global Wind Energy ETF
FAN
$278M
| $17.6K | ﹤0.01% |
862
+518
| +151% | +$10.4K |
|
6587
CALL
i3 Verticals
IIIV
$412M
| $17.6K | ﹤0.01% |
700
| – | – |
|
6588
PUT
Nomura Holdings
NMR
$28.3B
| $17.6K | ﹤0.01% |
2,100
+200
| +11% | +$1.49K |
|
6589
Standard Motor Products
SMP
$851M
| $17.6K | ﹤0.01% |
477
+248
| +108% | +$9.52K |
|
6590
CALL
Federal Agricultural Mortgage Class A
AGM.A
| $17.6K | ﹤0.01% |
100
-1,100
| -92% | -$139K |
|
6591
PUT
Descartes Systems
DSGX
$6.44B
| $17.5K | ﹤0.01% |
200
-900
| -82% | -$80.4K |
|
|
TPH
6592
DELISTED
Tri Pointe Homes
TPH
| $17.5K | ﹤0.01% |
+557
| New | +$18.1K |
|
6593
CALL
CareCloud
CCLD
$104M
| $17.5K | ﹤0.01% |
6,000
-22,200
| -79% | -$70.2K |
|
|
UMH
6594
CALL
UMH Properties
UMH
$1.29B
| $17.5K | ﹤0.01% |
1,100
-200
| -15% | -$3K |
|
|
CEPU
6595
PUT
Central Puerto
CEPU
$2.29B
| $17.5K | ﹤0.01% |
1,000
-1,000
| -50% | -$13.8K |
|
|
OPTU
6596
PUT
Optimum Communications Inc
OPTU
$298M
| $17.5K | ﹤0.01% |
10,600
-12,300
| -54% | -$25K |
|
6597
UNIFI
UFI
$119M
| $17.5K | ﹤0.01% |
4,996
-23,632
| -83% | -$91.3K |
|
6598
CALL
Solid Biosciences
SLDB
$794M
| $17.5K | ﹤0.01% |
3,100
-2,100
| -40% | -$11.4K |
|
|
CRCA
6599
ProShares Ultra CRCL
CRCA
$78.9M
| $17.5K | ﹤0.01% |
432
-441
| -51% | -$37.8K |
|
6600
PUT
Inseego
INSG
$114M
| $17.5K | ﹤0.01% |
1,700
+900
| +113% | +$11.7K |
|
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.