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 | |
|---|---|---|---|---|---|---|
|
NA
5551
PUT
Nano Labs
NA
$41.6M
| $56.4K | ﹤0.01% |
17,900
-64,200
| -78% | -$276K |
|
5552
CALL
Medpace
MEDP
$16.1B
| $56.2K | ﹤0.01% |
100
-1,900
| -95% | -$1.08M |
|
|
5553
PUT
Medpace
MEDP
$16.1B
| $56.2K | ﹤0.01% |
100
-7,000
| -99% | -$3.97M |
|
5554
PUT
Sun Life Financial
SLF
$46B
| $56.2K | ﹤0.01% |
900
+300
| +50% | +$18.1K |
|
5555
CALL
Central Pacific Financial
CPF
$1.02B
| $56.1K | ﹤0.01% |
1,800
-500
| -22% | -$15.1K |
|
|
WBTN
5556
CALL
WEBTOON Entertainment Inc
WBTN
$1.23B
| $56K | ﹤0.01% |
4,300
-11,700
| -73% | -$179K |
|
5557
Pliant Therapeutics
PLRX
$64.4M
| $56K | ﹤0.01% |
45,912
+32,923
| +253% | +$49.5K |
|
|
BTM
5558
CALL
DELISTED
Bitcoin Depot
BTM
| $56K | ﹤0.01% |
6,200
-16,971
| -73% | -$260K |
|
5559
CALL
Safe Bulkers
SB
$795M
| $55.9K | ﹤0.01% |
11,600
+9,500
| +452% | +$45.1K |
|
5560
CALL
Cohu
COHU
$2.26B
| $55.8K | ﹤0.01% |
2,400
-11,300
| -82% | -$259K |
|
5561
PUT
Annovis Bio
ANVS
$74.4M
| $55.7K | ﹤0.01% |
16,100
-2,400
| -13% | -$7.21K |
|
5562
Savara
SVRA
$1.12B
| $55.7K | ﹤0.01% |
9,235
-1,067
| -10% | -$5.23K |
|
5563
PUT
MediaAlpha
MAX
$758M
| $55.7K | ﹤0.01% |
4,300
+1,700
| +65% | +$20.8K |
|
5564
PUT
Gaotu Techedu
GOTU
$434M
| $55.7K | ﹤0.01% |
24,000
-50,400
| -68% | -$137K |
|
5565
CALL
WisdomTree US Total Dividend Fund
DTD
$1.65B
| $55.7K | ﹤0.01% |
700
-3,000
| -81% | -$253K |
|
5566
CALL
DNOW Inc
DNOW
$2.58B
| $55.6K | ﹤0.01% |
4,200
+2,000
| +91% | +$28.1K |
|
5567
PUT
Mid-America Apartment Communities
MAA
$15.4B
| $55.6K | ﹤0.01% |
400
-600
| -60% | -$79.9K |
|
5568
CALL
Compugen
CGEN
$222M
| $55.5K | ﹤0.01% |
36,300
+19,500
| +116% | +$32.4K |
|
|
ATYR
5569
PUT
aTyr Pharma
ATYR
$47.6M
| $55.5K | ﹤0.01% |
70,900
-249,600
| -78% | -$205K |
|
5570
Riskified
RSKD
$694M
| $55.5K | ﹤0.01% |
11,164
-55,114
| -83% | -$265K |
|
5571
PUT
PetMed Express
PETS
$41.7M
| $55.4K | ﹤0.01% |
17,300
-15,300
| -47% | -$38.4K |
|
5572
CALL
Goldman Sachs Physical Gold ETF Shares
AAAU
$2.46B
| $55.3K | ﹤0.01% |
1,300
-9,800
| -88% | -$402K |
|
5573
CALL
Regency Centers
REG
$14.7B
| $55.2K | ﹤0.01% |
800
+300
| +60% | +$21K |
|
5574
CALL
Real Brokerage
REAX
$349M
| $55.1K | ﹤0.01% |
15,100
-12,300
| -45% | -$47.5K |
|
5575
CALL
Methode Electronics
MEI
$496M
| $55.1K | ﹤0.01% |
8,300
+2,600
| +46% | +$18.4K |
|
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.