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 | |
|---|---|---|---|---|---|---|
2101
Range Resources
RRC
$9.11B
| $1.73M | ﹤0.01% |
49,110
+14,560
| +42% | +$542K |
|
2102
PUT
State Street
STT
$50.9B
| $1.73M | ﹤0.01% |
13,400
-1,000
| -7% | -$120K |
|
2103
PUT
Guardant Health
GH
$19.5B
| $1.73M | ﹤0.01% |
16,900
-34,100
| -67% | -$3.05M |
|
|
NNDM
2104
PUT
Nano Dimension
NNDM
$309M
| $1.72M | ﹤0.01% |
1,118,600
-900
| -0.1% | -$1.52K |
|
2105
CALL
Nasdaq
NDAQ
$51.5B
| $1.72M | ﹤0.01% |
17,700
-24,900
| -58% | -$2.24M |
|
2106
CALL
James Hardie Industries
JHX
$15.4B
| $1.72M | ﹤0.01% |
82,800
-360,800
| -81% | -$7.24M |
|
2107
CALL
Bumble
BMBL
$367M
| $1.72M | ﹤0.01% |
481,200
+246,200
| +105% | +$1.09M |
|
2108
PUT
Pitney Bowes
PBI
$2.42B
| $1.71M | ﹤0.01% |
162,100
-45,100
| -22% | -$468K |
|
2109
Howmet Aerospace
HWM
$116B
| $1.71M | ﹤0.01% |
+8,357
| New | +$1.66M |
|
2110
CALL
Emcor
EME
$33.1B
| $1.71M | ﹤0.01% |
2,800
-500
| -15% | -$324K |
|
2111
PUT
Texas Roadhouse
TXRH
$12.7B
| $1.71M | ﹤0.01% |
10,300
+3,300
| +47% | +$558K |
|
2112
CALL
TETRA Technologies
TTI
$1.23B
| $1.71M | ﹤0.01% |
182,300
-317,200
| -64% | -$2.45M |
|
|
SW
2113
PUT
Smurfit Westrock
SW
$25.5B
| $1.71M | ﹤0.01% |
44,100
+29,800
| +208% | +$1.14M |
|
2114
CALL
RingCentral
RNG
$4.05B
| $1.7M | ﹤0.01% |
59,000
-2,300
| -4% | -$65.5K |
|
2115
CALL
L3Harris
LHX
$55.9B
| $1.7M | ﹤0.01% |
5,800
-18,800
| -76% | -$5.43M |
|
2116
PUT
ZTO Express
ZTO
$18.2B
| $1.7M | ﹤0.01% |
81,500
-19,700
| -19% | -$390K |
|
2117
CALL
Western Alliance Bancorporation
WAL
$9.07B
| $1.69M | ﹤0.01% |
20,100
-20,200
| -50% | -$1.64M |
|
2118
PUT
Dianthus Therapeutics
DNTH
$5.68B
| $1.69M | ﹤0.01% |
41,000
+30,400
| +287% | +$1.18M |
|
2119
PUT
Aramark
ARMK
$15B
| $1.69M | ﹤0.01% |
45,800
-6,700
| -13% | -$255K |
|
2120
CALL
Finance of America Companies
FOA
$204M
| $1.69M | ﹤0.01% |
69,700
+18,500
| +36% | +$421K |
|
2121
CALL
ACM Research
ACMR
$5.83B
| $1.68M | ﹤0.01% |
42,700
-149,100
| -78% | -$5.56M |
|
|
TE
2122
PUT
T1 Energy
TE
$1.4B
| $1.68M | ﹤0.01% |
251,700
+179,800
| +250% | +$793K |
|
2123
PUT
TripAdvisor
TRIP
$1.59B
| $1.68M | ﹤0.01% |
115,400
-165,500
| -59% | -$2.52M |
|
2124
PUT
Air Products & Chemicals
APD
$66.3B
| $1.68M | ﹤0.01% |
6,800
+3,800
| +127% | +$963K |
|
2125
Pinduoduo
PDD
$118B
| $1.68M | ﹤0.01% |
14,795
-448,657
| -97% | -$55.7M |
|
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.