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 | |
|---|---|---|---|---|---|---|
|
STEX
4426
PUT
Streamex Corp
STEX
$71.8M
| $166K | ﹤0.01% |
54,900
+26,200
| +91% | +$117K |
|
4427
PUT
E.W. Scripps
SSP
$270M
| $166K | ﹤0.01% |
41,600
+38,800
| +1,386% | +$131K |
|
|
ABTC
4428
CALL
American Bitcoin Corp
ABTC
$379M
| $166K | ﹤0.01% |
6,507
-9,000
| -58% | -$563K |
|
4429
LoveSac
LOVE
$242M
| $166K | ﹤0.01% |
+11,247
| New | +$159K |
|
4430
CALL
Packaging Corp of America
PKG
$22.2B
| $165K | ﹤0.01% |
800
-700
| -47% | -$142K |
|
4431
CALL
10x Genomics
TXG
$5.88B
| $165K | ﹤0.01% |
10,100
-164,200
| -94% | -$2.48M |
|
4432
ThredUp
TDUP
$765M
| $165K | ﹤0.01% |
+25,779
| New | +$209K |
|
4433
PUT
Westwater Resources
WWR
$49.7M
| $165K | ﹤0.01% |
+219,500
| New | +$273K |
|
4434
PUT
American Battery Technology Co
ABAT
$280M
| $164K | ﹤0.01% |
49,200
-10,200
| -17% | -$47.7K |
|
4435
CALL
Flowers Foods
FLO
$1.58B
| $164K | ﹤0.01% |
15,100
-7,400
| -33% | -$85.9K |
|
4436
CALL
Spire Global
SPIR
$408M
| $164K | ﹤0.01% |
21,900
-8,400
| -28% | -$82.2K |
|
4437
Evolus
EOLS
$397M
| $164K | ﹤0.01% |
24,684
+19,295
| +358% | +$131K |
|
4438
Forte Biosciences
FBRX
$1.57B
| $164K | ﹤0.01% |
+6,015
| New | +$105K |
|
4439
ProShares Short Bitcoin Strategy ETF
BITI
$106M
| $163K | ﹤0.01% |
+7,049
| New | +$147K |
|
4440
Zura Bio
ZURA
$504M
| $163K | ﹤0.01% |
+31,161
| New | +$123K |
|
|
MNRS
4441
Grayscale Bitcoin Miners ETF
MNRS
$10.5M
| $163K | ﹤0.01% |
+5,437
| New | +$219K |
|
4442
New Mountain Finance
NMFC
$654M
| $163K | ﹤0.01% |
+17,727
| New | +$167K |
|
4443
Lightbridge
LTBR
$251M
| $163K | ﹤0.01% |
12,897
+1,968
| +18% | +$37.9K |
|
4444
PUT
Fortress Biotech
FBIO
$111M
| $163K | ﹤0.01% |
44,500
-26,900
| -38% | -$76.7K |
|
|
TWO
4445
CALL
Two Harbors Investment
TWO
$1.27B
| $163K | ﹤0.01% |
15,500
-19,400
| -56% | -$194K |
|
|
HNGE
4446
PUT
Hinge Health
HNGE
$5.73B
| $163K | ﹤0.01% |
3,500
-19,900
| -85% | -$958K |
|
4447
PUT
Endava
DAVA
$165M
| $162K | ﹤0.01% |
25,700
-39,500
| -61% | -$302K |
|
|
AIRJ
4448
Montana Technologies Corp
AIRJ
$291M
| $162K | ﹤0.01% |
41,219
+5,807
| +16% | +$25.1K |
|
4449
CALL
Viper Energy
VNOM
$8.43B
| $162K | ﹤0.01% |
4,200
-26,300
| -86% | -$996K |
|
|
NAKA
4450
CALL
Nakamoto Inc
NAKA
$74.5M
| $162K | ﹤0.01% |
11,533
-3,707
| -24% | -$96.9K |
|
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.