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 | |
|---|---|---|---|---|---|---|
4976
CytomX Therapeutics
CTMX
$675M
| $102K | ﹤0.01% |
+24,051
| New | +$91.4K |
|
|
CVGW
4977
PUT
DELISTED
Calavo Growers
CVGW
| $102K | ﹤0.01% |
4,700
+1,800
| +62% | +$39.9K |
|
4978
CALL
Integer Holdings
ITGR
$4.12B
| $102K | ﹤0.01% |
+1,300
| New | +$104K |
|
|
CIM
4979
PUT
Chimera Investment
CIM
$1.04B
| $102K | ﹤0.01% |
8,200
-97,000
| -92% | -$1.23M |
|
4980
Vipshop
VIPS
$7.37B
| $102K | ﹤0.01% |
5,761
-69,239
| -92% | -$1.33M |
|
4981
Fidus Investment
FDUS
$749M
| $102K | ﹤0.01% |
5,278
+2,702
| +105% | +$53.7K |
|
|
HYFT
4982
MindWalk Holdings
HYFT
$60.6M
| $102K | ﹤0.01% |
+55,823
| New | +$98.3K |
|
4983
PUT
MDU Resources
MDU
$4.17B
| $102K | ﹤0.01% |
5,200
| – | – |
|
|
SRTA
4984
CALL
Strata Critical Medical Inc
SRTA
$434M
| $101K | ﹤0.01% |
21,100
-8,000
| -27% | -$38.7K |
|
4985
PUT
Archrock
AROC
$6.27B
| $101K | ﹤0.01% |
3,900
+100
| +3% | +$2.49K |
|
4986
PUT
Healthpeak Properties
DOC
$15.1B
| $101K | ﹤0.01% |
6,300
-5,400
| -46% | -$95.2K |
|
4987
PUT
Lamar Advertising Co
LAMR
$16.2B
| $101K | ﹤0.01% |
800
-21,400
| -96% | -$2.68M |
|
|
ANGX
4988
Angel Studios
ANGX
$757M
| $101K | ﹤0.01% |
+21,671
| New | +$128K |
|
|
FOLD
4989
CALL
DELISTED
Amicus Therapeutics
FOLD
| $101K | ﹤0.01% |
7,100
-28,100
| -80% | -$276K |
|
|
CAN
4990
PUT
Canaan Creative
CAN
$127M
| $101K | ﹤0.01% |
146,400
+124,300
| +562% | +$142K |
|
4991
CALL
LifeMD
LFMD
$169M
| $101K | ﹤0.01% |
29,600
+8,000
| +37% | +$38.8K |
|
4992
CALL
Orchestra BioMed
OBIO
$238M
| $101K | ﹤0.01% |
+24,300
| New | +$98K |
|
4993
iShares Core International Aggregate Bond Fund
IAGG
$10.9B
| $101K | ﹤0.01% |
+2,013
| New | +$104K |
|
|
VTEL
4994
CALL
Vanguard Long-Term Tax-Exempt Bond ETF
VTEL
$281M
| $101K | ﹤0.01% |
+2,000
| New | +$208K |
|
4995
QuidelOrtho
QDEL
$1.14B
| $101K | ﹤0.01% |
3,519
+1,297
| +58% | +$35.1K |
|
|
IRBT
4996
PUT
DELISTED
iRobot
IRBT
| $100K | ﹤0.01% |
913,500
+349,200
| +62% | +$1.05M |
|
4997
PubMatic
PUBM
$585M
| $100K | ﹤0.01% |
+11,327
| New | +$98.7K |
|
|
JAMF
4998
DELISTED
Jamf
JAMF
| $100K | ﹤0.01% |
+7,719
| New | +$93.7K |
|
4999
CALL
Worthington Steel
WS
$1.8B
| $100K | ﹤0.01% |
2,900
+2,600
| +867% | +$85.5K |
|
|
MVLL
5000
GraniteShares 2x Long MRVL Daily ETF
MVLL
$220M
| $100K | ﹤0.01% |
13,962
+10,182
| +269% | +$82.3K |
|
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.