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 | |
|---|---|---|---|---|---|---|
1126
PUT
Ondas Inc
ONDS
$4.52B
| $6.26M | ﹤0.01% |
641,900
-797,600
| -55% | -$6.41M |
|
1127
PUT
Sempra
SRE
$61.1B
| $6.26M | ﹤0.01% |
70,900
-32,500
| -31% | -$2.96M |
|
|
FITB
1128
CALL
Fifth Third Bancorp
FITB
$51.8B
| $6.26M | ﹤0.01% |
133,700
+36,000
| +37% | +$1.58M |
|
1129
PUT
Motorola Solutions
MSI
$67.6B
| $6.25M | ﹤0.01% |
16,300
+12,800
| +366% | +$5.14M |
|
1130
CALL
Stellantis
STLA
$16.7B
| $6.24M | ﹤0.01% |
573,200
-134,200
| -19% | -$1.44M |
|
1131
CALL
STMicroelectronics
STM
$47.7B
| $6.24M | ﹤0.01% |
240,600
+123,800
| +106% | +$3.18M |
|
1132
PUT
Prudential Financial
PRU
$40.9B
| $6.2M | ﹤0.01% |
54,900
-68,900
| -56% | -$7.39M |
|
1133
Amphenol
APH
$194B
| $6.19M | ﹤0.01% |
45,822
+26,920
| +142% | +$3.6M |
|
1134
PUT
Kroger
KR
$34.2B
| $6.19M | ﹤0.01% |
99,100
-170,000
| -63% | -$11.1M |
|
1135
CALL
American Tower
AMT
$76.7B
| $6.18M | ﹤0.01% |
35,200
-26,400
| -43% | -$4.8M |
|
1136
CALL
Norfolk Southern
NSC
$78.3B
| $6.18M | ﹤0.01% |
21,400
+3,700
| +21% | +$1.07M |
|
1137
PUT
Flutter Entertainment
FLUT
$17.5B
| $6.15M | ﹤0.01% |
28,600
+16,300
| +133% | +$3.67M |
|
1138
Lam Research
LRCX
$400B
| $6.12M | ﹤0.01% |
+35,760
| New | +$5.56M |
|
1139
CALL
NextDecade
NEXT
$2.11B
| $6.12M | ﹤0.01% |
1,161,300
+434,600
| +60% | +$2.59M |
|
|
USAR
1140
CALL
USA Rare Earth Inc
USAR
$3.7B
| $6.12M | ﹤0.01% |
514,100
+43,500
| +9% | +$829K |
|
1141
CALL
Waste Management
WM
$95.3B
| $6.11M | ﹤0.01% |
27,800
-88,400
| -76% | -$18.8M |
|
1142
PUT
AES
AES
$10.6B
| $6.11M | ﹤0.01% |
425,900
-1,400
| -0.3% | -$19.7K |
|
1143
PUT
Toyota
TM
$209B
| $6.1M | ﹤0.01% |
28,500
-5,300
| -16% | -$1.08M |
|
1144
PUT
Ross Stores
ROST
$74.5B
| $6.07M | ﹤0.01% |
33,700
-20,300
| -38% | -$3.39M |
|
1145
PUT
American Electric Power
AEP
$73.4B
| $6.07M | ﹤0.01% |
52,600
-45,100
| -46% | -$5.33M |
|
1146
PUT
The Mosaic Company
MOS
$7.08B
| $6.06M | ﹤0.01% |
251,500
+24,900
| +11% | +$671K |
|
1147
CALL
argenx
ARGX
$57.8B
| $6.05M | ﹤0.01% |
7,200
-2,000
| -22% | -$1.71M |
|
1148
CALL
AeroVironment
AVAV
$8.03B
| $6.05M | ﹤0.01% |
25,000
+3,700
| +17% | +$1.16M |
|
1149
CALL
Quanta Services
PWR
$98.1B
| $6.04M | ﹤0.01% |
14,300
-10,200
| -42% | -$4.48M |
|
1150
CALL
Wingstop
WING
$3.67B
| $5.99M | ﹤0.01% |
25,100
+13,300
| +113% | +$3.29M |
|
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.