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 | |
|---|---|---|---|---|---|---|
6976
Zegna
ZGN
$3.98B
| $10.1K | ﹤0.01% |
+989
| New | +$10.1K |
|
6977
Oportun Financial
OPRT
$259M
| $10.1K | ﹤0.01% |
1,916
-6,008
| -76% | -$31.7K |
|
6978
Cytek Biosciences
CTKB
$557M
| $10.1K | ﹤0.01% |
2,003
+1,318
| +192% | +$6.12K |
|
6979
PUT
W&T Offshore
WTI
$515M
| $10.1K | ﹤0.01% |
6,200
-45,400
| -88% | -$87.2K |
|
|
HUYA
6980
PUT
Huya Inc
HUYA
$570M
| $10.1K | ﹤0.01% |
3,500
| – | – |
|
|
EATZ
6981
DELISTED
AdvisorShares Restaurant ETF
EATZ
| $10.1K | ﹤0.01% |
+388
| New | +$10.2K |
|
|
RYZ
6982
CALL
Ryerson Holding Corp
RYZ
$1.39B
| $10.1K | ﹤0.01% |
400
-100
| -20% | -$2.3K |
|
6983
Zumiez
ZUMZ
$334M
| $10K | ﹤0.01% |
385
+379
| +6,317% | +$9.1K |
|
|
BZUN
6984
Baozun
BZUN
$173M
| $10K | ﹤0.01% |
3,764
-10,184
| -73% | -$32K |
|
6985
CALL
First Financial Bancorp
FFBC
$3.55B
| $10K | ﹤0.01% |
400
+300
| +300% | +$7.49K |
|
6986
PUT
Playboy Inc
PLBY
$133M
| $9.96K | ﹤0.01% |
5,300
+800
| +18% | +$1.31K |
|
6987
PUT
Riskified
RSKD
$701M
| $9.94K | ﹤0.01% |
2,000
-85,900
| -98% | -$414K |
|
|
FINV
6988
PUT
FinVolution Group
FINV
$1.15B
| $9.94K | ﹤0.01% |
1,900
-30,100
| -94% | -$177K |
|
|
IRS
6989
PUT
IRSA Inversiones y Representaciones
IRS
$1.31B
| $9.92K | ﹤0.01% |
600
+100
| +20% | +$1.44K |
|
6990
CALL
Provident Financial Services
PFS
$3.24B
| $9.88K | ﹤0.01% |
+500
| New | +$9.67K |
|
|
CHCT
6991
CALL
Community Healthcare Trust
CHCT
$530M
| $9.85K | ﹤0.01% |
600
-1,200
| -67% | -$17.9K |
|
6992
Universal Insurance Holdings
UVE
$1.23B
| $9.84K | ﹤0.01% |
+291
| New | +$9.28K |
|
6993
PUT
Coherus Oncology
CHRS
$227M
| $9.8K | ﹤0.01% |
6,900
| – | – |
|
6994
PUT
Neuronetics
STIM
$137M
| $9.8K | ﹤0.01% |
7,100
-25,300
| -78% | -$52.9K |
|
|
TDAY
6995
PUT
USA Today Co
TDAY
$1.28B
| $9.79K | ﹤0.01% |
1,900
-36,600
| -95% | -$172K |
|
6996
Global X US Preferred ETF
PFFD
$2.15B
| $9.78K | ﹤0.01% |
517
+136
| +36% | +$2.6K |
|
6997
ProShares UltraPro Short 20+ Year Treasury
TTT
$19M
| $9.77K | ﹤0.01% |
146
+111
| +317% | +$7.46K |
|
6998
LiveOne
LVO
$61.6M
| $9.77K | ﹤0.01% |
2,070
+2,067
| +68,900% | +$9.79K |
|
|
AMRN
6999
CALL
Amarin Corp
AMRN
$298M
| $9.77K | ﹤0.01% |
700
-11,900
| -94% | -$196K |
|
7000
CALL
Amerant Bancorp
AMTB
$1.16B
| $9.76K | ﹤0.01% |
+500
| New | +$9.31K |
|
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.