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 | |
|---|---|---|---|---|---|---|
2026
Pagaya Technologies
PGY
$1.32B
| $1.9M | ﹤0.01% |
90,760
-79,790
| -47% | -$2.03M |
|
2027
CALL
Vermilion Energy
VET
$1.73B
| $1.89M | ﹤0.01% |
227,000
-107,500
| -32% | -$887K |
|
2028
Enphase Energy
ENPH
$4.84B
| $1.89M | ﹤0.01% |
59,055
+34,965
| +145% | +$1.13M |
|
2029
CALL
Scorpio Tankers
STNG
$3.96B
| $1.89M | ﹤0.01% |
37,200
-50,100
| -57% | -$2.86M |
|
2030
Unity
U
$12.5B
| $1.89M | ﹤0.01% |
+42,783
| New | +$1.74M |
|
2031
CALL
Bausch Health
BHC
$1.65B
| $1.89M | ﹤0.01% |
271,600
-76,500
| -22% | -$503K |
|
2032
PUT
Factset
FDS
$9.05B
| $1.89M | ﹤0.01% |
6,500
-2,700
| -29% | -$758K |
|
2033
CALL
Sony
SONY
$123B
| $1.88M | ﹤0.01% |
195,100
-171,000
| -47% | -$4.8M |
|
|
FLY
2034
CALL
Firefly Aerospace
FLY
$3.23B
| $1.87M | ﹤0.01% |
83,700
+43,600
| +109% | +$1.01M |
|
2035
CALL
TransAlta
TAC
$4.34B
| $1.87M | ﹤0.01% |
147,800
+109,500
| +286% | +$1.63M |
|
2036
Dave Inc
DAVE
$5.12B
| $1.87M | ﹤0.01% |
8,427
+4,900
| +139% | +$1.05M |
|
2037
PUT
Synaptics
SYNA
$4.41B
| $1.87M | ﹤0.01% |
25,200
+24,300
| +2,700% | +$1.71M |
|
|
VISN
2038
Vistance Networks Inc
VISN
$2.66B
| $1.86M | ﹤0.01% |
102,823
+53,779
| +110% | +$928K |
|
2039
CALL
Omnicom Group
OMC
$22.7B
| $1.86M | ﹤0.01% |
23,000
-10,100
| -31% | -$772K |
|
2040
CALL
ASE Group
ASX
$80.8B
| $1.85M | ﹤0.01% |
115,100
+99,400
| +633% | +$1.41M |
|
2041
PUT
Tiptree Inc
TIPT
$668M
| $1.85M | ﹤0.01% |
101,300
-21,700
| -18% | -$395K |
|
2042
Transocean
RIG
$5.92B
| $1.85M | ﹤0.01% |
448,107
-916,219
| -67% | -$3.56M |
|
2043
CALL
Stride
LRN
$3.69B
| $1.85M | ﹤0.01% |
28,500
-36,800
| -56% | -$3.34M |
|
2044
Designer Brands
DBI
$277M
| $1.85M | ﹤0.01% |
248,744
+171,120
| +220% | +$823K |
|
2045
AbbVie
ABBV
$458B
| $1.85M | ﹤0.01% |
8,076
-98,008
| -92% | -$22.3M |
|
2046
ACV Auctions
ACVA
$1.35B
| $1.84M | ﹤0.01% |
229,883
+199,186
| +649% | +$1.61M |
|
2047
PUT
Cooper Companies
COO
$13.7B
| $1.84M | ﹤0.01% |
22,400
+17,300
| +339% | +$1.29M |
|
2048
CALL
Comstock Resources
CRK
$3.97B
| $1.83M | ﹤0.01% |
79,100
-22,900
| -22% | -$505K |
|
2049
PUT
Summit Therapeutics
SMMT
$10.9B
| $1.83M | ﹤0.01% |
104,800
-35,500
| -25% | -$668K |
|
2050
Cogent Communications
CCOI
$594M
| $1.83M | ﹤0.01% |
+84,895
| New | +$2.51M |
|
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.