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 | |
|---|---|---|---|---|---|---|
1926
PUT
Modine Manufacturing
MOD
$12.8B
| $2.14M | ﹤0.01% |
16,000
+6,500
| +68% | +$968K |
|
1927
Omeros
OMER
$709M
| $2.13M | ﹤0.01% |
123,979
+101,759
| +458% | +$876K |
|
1928
PUT
Lightpath Technologies
LPTH
$680M
| $2.12M | ﹤0.01% |
196,600
+12,200
| +7% | +$98.8K |
|
1929
CALL
Alaska Air
ALK
$5.15B
| $2.12M | ﹤0.01% |
42,100
-152,100
| -78% | -$7.03M |
|
1930
CALL
OR Royalties Inc
OR
$5.47B
| $2.12M | ﹤0.01% |
59,800
-18,000
| -23% | -$631K |
|
1931
CALL
Bank of Montreal
BMO
$125B
| $2.12M | ﹤0.01% |
16,300
-3,100
| -16% | -$393K |
|
|
NNE
1932
PUT
Nano Nuclear Energy
NNE
$813M
| $2.11M | ﹤0.01% |
88,000
-43,900
| -33% | -$1.68M |
|
1933
PUT
Grindr
GRND
$2.64B
| $2.11M | ﹤0.01% |
156,000
+150,400
| +2,686% | +$2.04M |
|
1934
Upstart Holdings
UPST
$2.58B
| $2.11M | ﹤0.01% |
+48,172
| New | +$2.22M |
|
1935
CALL
Equifax
EFX
$20.3B
| $2.1M | ﹤0.01% |
9,700
-4,600
| -32% | -$1.01M |
|
1936
CALL
PagSeguro Digital
PAGS
$2.57B
| $2.1M | ﹤0.01% |
218,300
-14,200
| -6% | -$136K |
|
1937
PUT
InterDigital
IDCC
$6.68B
| $2.1M | ﹤0.01% |
6,600
+500
| +8% | +$177K |
|
1938
CALL
Box
BOX
$4.02B
| $2.1M | ﹤0.01% |
70,100
-73,700
| -51% | -$2.31M |
|
1939
PUT
Nuvation Bio
NUVB
$2.24B
| $2.09M | ﹤0.01% |
233,600
-73,100
| -24% | -$453K |
|
1940
PUT
Howmet Aerospace
HWM
$116B
| $2.09M | ﹤0.01% |
10,200
-76,600
| -88% | -$15.2M |
|
1941
Crocs
CROX
$6.69B
| $2.09M | ﹤0.01% |
24,405
-57,291
| -70% | -$4.79M |
|
1942
State Street Financial Select Sector SPDR ETF
XLF
$55.6B
| $2.09M | ﹤0.01% |
+38,079
| New | +$2.03M |
|
1943
PUT
POET Technologies
POET
$1.19B
| $2.09M | ﹤0.01% |
329,400
+286,700
| +671% | +$1.82M |
|
1944
PUT
Braze
BRZE
$2.45B
| $2.08M | ﹤0.01% |
60,800
+56,000
| +1,167% | +$1.66M |
|
1945
PUT
BRC Group Holdings
RILY
$277M
| $2.08M | ﹤0.01% |
445,800
+44,600
| +11% | +$221K |
|
1946
PUT
Royal Bank of Canada
RY
$291B
| $2.08M | ﹤0.01% |
12,200
-22,600
| -65% | -$3.47M |
|
1947
PUT
Viking Holdings
VIK
$44.9B
| $2.08M | ﹤0.01% |
29,100
-12,700
| -30% | -$810K |
|
1948
PUT
Mattel
MAT
$4.17B
| $2.08M | ﹤0.01% |
104,600
-8,400
| -7% | -$162K |
|
|
RZLV
1949
CALL
Rezolve AI
RZLV
$893M
| $2.07M | ﹤0.01% |
806,800
-90,800
| -10% | -$343K |
|
1950
PUT
Varonis Systems
VRNS
$5.25B
| $2.07M | ﹤0.01% |
63,100
+62,800
| +20,933% | +$2.64M |
|
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.