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 | |
|---|---|---|---|---|---|---|
7126
PUT
Sutro Biopharma
STRO
$386M
| $8.1K | ﹤0.01% |
+700
| New | +$6.64K |
|
7127
CALL
Mama's Creations
MAMA
$846M
| $8.09K | ﹤0.01% |
600
-53,700
| -99% | -$617K |
|
7128
CALL
Otter Tail
OTTR
$3.81B
| $8.08K | ﹤0.01% |
+100
| New | +$8.1K |
|
7129
CALL
Cytek Biosciences
CTKB
$566M
| $8.08K | ﹤0.01% |
+1,600
| New | +$7.43K |
|
7130
Gaotu Techedu
GOTU
$405M
| $8.06K | ﹤0.01% |
3,475
-99,093
| -97% | -$269K |
|
7131
PUT
Yext
YEXT
$573M
| $8.06K | ﹤0.01% |
1,000
-45,200
| -98% | -$381K |
|
|
NVDG
7132
Leverage Shares 2X Long NVDA Daily ETF
NVDG
$37.6M
| $8.05K | ﹤0.01% |
478
-2,398
| -83% | -$46.3K |
|
|
PLCY
7133
PUT
DELISTED
EventShares U.S. Legislative Opportunities ETF
PLCY
| $8.05K | ﹤0.01% |
400
+100
| +33% | +$2.01K |
|
|
KIDZ
7134
CALL
KIDZ AI Inc Class B
KIDZ
$1.23M
| $8.01K | ﹤0.01% |
90
-30
| -25% | -$8.54K |
|
7135
PUT
Arcturus Therapeutics
ARCT
$165M
| $7.97K | ﹤0.01% |
1,300
-116,600
| -99% | -$1.26M |
|
7136
SunCoke Energy
SXC
$794M
| $7.96K | ﹤0.01% |
1,106
-5,127
| -82% | -$37.7K |
|
7137
CALL
Personalis
PSNL
$1.25B
| $7.96K | ﹤0.01% |
1,000
-4,800
| -83% | -$42K |
|
7138
PUT
MeiraGTx Holdings
MGTX
$1.08B
| $7.95K | ﹤0.01% |
1,000
-1,500
| -60% | -$12.5K |
|
7139
CALL
CarParts.com
PRTS
$42.6M
| $7.95K | ﹤0.01% |
+1,590
| New | +$8.9K |
|
7140
PUT
Caribou Biosciences
CRBU
$146M
| $7.95K | ﹤0.01% |
5,000
+900
| +22% | +$1.89K |
|
|
HDSN
7141
Hudson Technologies
HDSN
$246M
| $7.95K | ﹤0.01% |
1,160
-14,707
| -93% | -$116K |
|
7142
CALL
Breakwave Tanker Shipping ETF
BWET
$33.4M
| $7.89K | ﹤0.01% |
900
-400
| -31% | -$7.89K |
|
7143
PUT
Toro Company
TTC
$8.79B
| $7.87K | ﹤0.01% |
100
-6,800
| -99% | -$503K |
|
7144
CALL
Compass Minerals
CMP
$1.23B
| $7.86K | ﹤0.01% |
400
+100
| +33% | +$1.85K |
|
7145
PUT
Caledonia Mining Corp
CMCL
$351M
| $7.85K | ﹤0.01% |
300
-400
| -57% | -$11.8K |
|
7146
PUT
Vir Biotechnology
VIR
$1.46B
| $7.84K | ﹤0.01% |
1,300
-1,900
| -59% | -$11.3K |
|
7147
PUT
US Physical Therapy
USPH
$1.22B
| $7.81K | ﹤0.01% |
+100
| New | +$8.12K |
|
|
AIOT
7148
PowerFleet Inc
AIOT
$537M
| $7.8K | ﹤0.01% |
1,467
-22,851
| -94% | -$117K |
|
|
CIO
7149
DELISTED
City Office REIT
CIO
| $7.79K | ﹤0.01% |
1,114
+1,081
| +3,276% | +$7.48K |
|
|
TTDU
7150
T-REX 2X Long TTD Daily Target ETF
TTDU
$13.6M
| $7.78K | ﹤0.01% |
+485
| New | +$11.4K |
|
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.