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 | |
|---|---|---|---|---|---|---|
4226
CALL
Dine Brands
DIN
$462M
| $202K | ﹤0.01% |
6,300
+2,500
| +66% | +$72.6K |
|
4227
ProShares Ultra Gold
UGL
$649M
| $202K | ﹤0.01% |
3,636
-71,040
| -95% | -$3.72M |
|
4228
PUT
HealthEquity
HQY
$8.71B
| $202K | ﹤0.01% |
2,200
+2,100
| +2,100% | +$201K |
|
4229
PUT
Weyerhaeuser
WY
$17.6B
| $201K | ﹤0.01% |
8,500
-8,900
| -51% | -$206K |
|
4230
Moody's
MCO
$83.7B
| $201K | ﹤0.01% |
394
+351
| +816% | +$171K |
|
4231
PUT
Landstar System
LSTR
$6.03B
| $201K | ﹤0.01% |
1,400
-8,300
| -86% | -$1.11M |
|
4232
CALL
American Century Diversified Corporate Bond ETF
KORP
$869M
| $201K | ﹤0.01% |
2,500
-9,600
| -79% | -$456K |
|
|
NMAX
4233
PUT
Newsmax Inc
NMAX
$987M
| $201K | ﹤0.01% |
26,000
-49,900
| -66% | -$479K |
|
4234
PUT
Brinker International
EAT
$8.82B
| $201K | ﹤0.01% |
1,400
-15,300
| -92% | -$2M |
|
4235
Modine Manufacturing
MOD
$9.46B
| $201K | ﹤0.01% |
+1,504
| New | +$224K |
|
4236
ProShares Ultra Bloomberg Crude Oil
UCO
$432M
| $201K | ﹤0.01% |
+10,383
| New | +$213K |
|
4237
Atlas Lithium Corp
ATLX
$75.5M
| $201K | ﹤0.01% |
47,406
+36,016
| +316% | +$182K |
|
|
BETA
4238
PUT
Beta Technologies Inc
BETA
$3.91B
| $200K | ﹤0.01% |
+7,100
| New | +$212K |
|
4239
BlackSky Technology
BKSY
$843M
| $200K | ﹤0.01% |
10,671
-1,381
| -11% | -$28.2K |
|
|
SARO
4240
StandardAero Inc
SARO
$9.55B
| $199K | ﹤0.01% |
6,947
+4,386
| +171% | +$119K |
|
4241
Tower Semiconductor
TSEM
$21.2B
| $199K | ﹤0.01% |
+1,696
| New | +$163K |
|
4242
Zurn Elkay Water Solutions
ZWS
$8.6B
| $199K | ﹤0.01% |
4,276
+244
| +6% | +$11.5K |
|
4243
Kopin
KOPN
$586M
| $198K | ﹤0.01% |
84,674
-37,159
| -30% | -$107K |
|
|
MOMO
4244
CALL
Hello Group
MOMO
$867M
| $198K | ﹤0.01% |
30,200
-1,500
| -5% | -$10.3K |
|
4245
CVR Partners
UAN
$1.3B
| $198K | ﹤0.01% |
1,929
-23,225
| -92% | -$2.21M |
|
4246
PUT
Rexford Industrial Realty
REXR
$8.63B
| $197K | ﹤0.01% |
5,100
-3,900
| -43% | -$161K |
|
4247
PUT
Invesco DB US Dollar Index Bullish Fund
UUP
$423M
| $197K | ﹤0.01% |
7,300
-64,200
| -90% | -$1.79M |
|
|
GLIBK
4248
PUT
Liberty Capital Corp Series C GCI Group Common Stock
GLIBK
$932M
| $197K | ﹤0.01% |
+5,300
| New | +$186K |
|
4249
Quadratic Interest Rate Volatility and Inflation Hedge ETF
IVOL
$274M
| $197K | ﹤0.01% |
10,287
-12,959
| -56% | -$250K |
|
4250
CALL
Mohawk Industries
MHK
$6.91B
| $197K | ﹤0.01% |
1,800
+1,200
| +200% | +$138K |
|
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.