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 | |
|---|---|---|---|---|---|---|
3251
Dutch Bros
BROS
$9.01B
| $530K | ﹤0.01% |
+8,660
| New | +$492K |
|
3252
PUT
Invesco DB Commodity Index Tracking Fund
DBC
$1.67B
| $530K | ﹤0.01% |
23,700
+17,700
| +295% | +$402K |
|
3253
PUT
Klaviyo
KVYO
$5.31B
| $529K | ﹤0.01% |
16,300
-57,200
| -78% | -$1.6M |
|
3254
PUT
Structure Therapeutics
GPCR
$3.46B
| $529K | ﹤0.01% |
7,600
-14,600
| -66% | -$596K |
|
3255
PUT
UWM Holdings
UWMC
$624M
| $528K | ﹤0.01% |
120,500
-130,000
| -52% | -$699K |
|
3256
PUT
Vanguard Dividend Appreciation ETF
VIG
$112B
| $527K | ﹤0.01% |
2,400
+2,000
| +500% | +$437K |
|
3257
Boot Barn
BOOT
$4.71B
| $527K | ﹤0.01% |
+2,988
| New | +$557K |
|
3258
PUT
Boston Beer
SAM
$1.91B
| $527K | ﹤0.01% |
2,700
+2,200
| +440% | +$454K |
|
|
ABTC
3259
American Bitcoin Corp
ABTC
$429M
| $527K | ﹤0.01% |
20,653
+20,487
| +12,342% | +$1.28M |
|
3260
PUT
Stride
LRN
$3.83B
| $526K | ﹤0.01% |
8,100
-20,200
| -71% | -$1.83M |
|
3261
PUT
Rhythm Pharmaceuticals
RYTM
$7.28B
| $524K | ﹤0.01% |
4,900
+4,600
| +1,533% | +$488K |
|
3262
CALL
Revvity
RVTY
$12.1B
| $522K | ﹤0.01% |
+5,400
| New | +$518K |
|
3263
CALL
Primoris Services
PRIM
$4.64B
| $521K | ﹤0.01% |
4,200
-8,400
| -67% | -$1.1M |
|
3264
VanEck BDC Income ETF
BIZD
$1.6B
| $521K | ﹤0.01% |
+36,768
| New | +$527K |
|
3265
APA Corp
APA
$12.3B
| $521K | ﹤0.01% |
+21,289
| New | +$515K |
|
3266
CALL
Quest Diagnostics
DGX
$25.6B
| $521K | ﹤0.01% |
3,000
-8,000
| -73% | -$1.46M |
|
3267
CALL
Digital Turbine
APPS
$1.04B
| $521K | ﹤0.01% |
104,100
-11,300
| -10% | -$64K |
|
3268
PUT
10x Genomics
TXG
$5.83B
| $520K | ﹤0.01% |
31,900
-34,600
| -52% | -$523K |
|
3269
PUT
US Gold Corp
USAU
$221M
| $520K | ﹤0.01% |
26,800
+18,700
| +231% | +$320K |
|
3270
CALL
Bloomin' Brands
BLMN
$731M
| $520K | ﹤0.01% |
84,300
+14,200
| +20% | +$98.9K |
|
3271
PUT
Glaukos
GKOS
$8.92B
| $519K | ﹤0.01% |
4,600
+1,200
| +35% | +$115K |
|
3272
CALL
CubeSmart
CUBE
$9.57B
| $519K | ﹤0.01% |
14,400
+7,000
| +95% | +$266K |
|
3273
PUT
EPR Properties
EPR
$4.85B
| $519K | ﹤0.01% |
10,400
-30,900
| -75% | -$1.61M |
|
3274
UroGen Pharma
URGN
$2.02B
| $518K | ﹤0.01% |
+22,109
| New | +$480K |
|
3275
Abeona Therapeutics
ABEO
$349M
| $518K | ﹤0.01% |
98,238
+65,466
| +200% | +$330K |
|
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.