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 | |
|---|---|---|---|---|---|---|
|
BETA
6001
Beta Technologies Inc
BETA
$4.37B
| $34.2K | ﹤0.01% |
+1,211
| New | +$36.1K |
|
6002
Velocity Financial
VEL
$689M
| $34.1K | ﹤0.01% |
1,644
-33,406
| -95% | -$627K |
|
6003
CALL
Loar Holdings
LOAR
$6.41B
| $34K | ﹤0.01% |
500
-12,600
| -96% | -$919K |
|
6004
Sprott Junior Gold Miners ETF
SGDJ
$267M
| $34K | ﹤0.01% |
+404
| New | +$31.7K |
|
6005
CALL
Everest Group
EG
$14.5B
| $33.9K | ﹤0.01% |
100
-1,200
| -92% | -$396K |
|
6006
PUT
Xerox
XRX
$387M
| $33.9K | ﹤0.01% |
14,300
-122,900
| -90% | -$364K |
|
6007
Laser Photonics
LASE
$49.2M
| $33.9K | ﹤0.01% |
13,717
-11,320
| -45% | -$38K |
|
6008
Credicorp
BAP
$31.8B
| $33.9K | ﹤0.01% |
118
-414
| -78% | -$110K |
|
6009
PUT
Zumiez
ZUMZ
$332M
| $33.9K | ﹤0.01% |
1,300
-9,600
| -88% | -$231K |
|
6010
Geospace Technologies
GEOS
$94.6M
| $33.8K | ﹤0.01% |
+2,001
| New | +$40.2K |
|
6011
MiMedx Group
MDXG
$602M
| $33.8K | ﹤0.01% |
+4,986
| New | +$34.9K |
|
6012
CALL
Alpha Pro Tech
APT
$50.4M
| $33.7K | ﹤0.01% |
7,600
-23,500
| -76% | -$108K |
|
6013
CALL
Sylvamo
SLVM
$1.49B
| $33.7K | ﹤0.01% |
700
-600
| -46% | -$27.3K |
|
6014
Akebia Therapeutics
AKBA
$354M
| $33.6K | ﹤0.01% |
20,895
-79,208
| -79% | -$166K |
|
6015
CALL
MSC Industrial Direct
MSM
$6.89B
| $33.6K | ﹤0.01% |
400
-7,700
| -95% | -$667K |
|
|
AMBR
6016
Amber International Holding Ltd
AMBR
$130M
| $33.6K | ﹤0.01% |
+19,412
| New | +$38.3K |
|
6017
CALL
Sutro Biopharma
STRO
$401M
| $33.6K | ﹤0.01% |
2,900
+2,600
| +867% | +$24.7K |
|
6018
J&J Snack Foods
JJSF
$1.43B
| $33.5K | ﹤0.01% |
371
+87
| +31% | +$7.89K |
|
6019
PUT
Atmos Energy
ATO
$28.8B
| $33.5K | ﹤0.01% |
+200
| New | +$34.6K |
|
6020
Blink Charging
BLNK
$74.3M
| $33.5K | ﹤0.01% |
50,168
-238,127
| -83% | -$344K |
|
6021
Weave Communications
WEAV
$520M
| $33.4K | ﹤0.01% |
4,396
+1,996
| +83% | +$13.3K |
|
6022
PUT
Orthofix Medical
OFIX
$477M
| $33.4K | ﹤0.01% |
2,200
-300
| -12% | -$4.58K |
|
6023
CALL
Grocery Outlet
GO
$909M
| $33.3K | ﹤0.01% |
3,300
-39,400
| -92% | -$496K |
|
6024
CALL
iHeartMedia
IHRT
$543M
| $33.3K | ﹤0.01% |
8,000
+7,100
| +789% | +$26.5K |
|
6025
CALL
Lithia Motors
LAD
$8.47B
| $33.2K | ﹤0.01% |
100
-100
| -50% | -$31.8K |
|
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.