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 | |
|---|---|---|---|---|---|---|
2001
PUT
Capricor Therapeutics
CAPR
$1.14B
| $1.96M | ﹤0.01% |
67,900
-102,500
| -60% | -$1.34M |
|
2002
Carlyle Group
CG
$16.3B
| $1.96M | ﹤0.01% |
+33,129
| New | +$1.88M |
|
2003
PUT
StoneCo
STNE
$2.62B
| $1.96M | ﹤0.01% |
132,400
-22,200
| -14% | -$371K |
|
2004
CALL
AvalonBay Communities
AVB
$27.1B
| $1.96M | ﹤0.01% |
10,800
-600
| -5% | -$109K |
|
2005
PUT
Allstate
ALL
$66.9B
| $1.96M | ﹤0.01% |
9,400
-38,200
| -80% | -$7.82M |
|
2006
PUT
Sweetgreen
SG
$713M
| $1.95M | ﹤0.01% |
289,000
-123,900
| -30% | -$852K |
|
2007
PUT
ResMed
RMD
$28.3B
| $1.95M | ﹤0.01% |
8,100
-6,800
| -46% | -$1.74M |
|
2008
PUT
Valaris
VAL
$5.51B
| $1.95M | ﹤0.01% |
38,700
-108,500
| -74% | -$5.82M |
|
2009
Coeur Mining
CDE
$15.6B
| $1.95M | ﹤0.01% |
+109,228
| New | +$1.9M |
|
2010
CALL
Advanced Energy
AEIS
$12.2B
| $1.95M | ﹤0.01% |
9,300
+8,700
| +1,450% | +$1.77M |
|
2011
Fastenal
FAST
$54B
| $1.94M | ﹤0.01% |
48,450
-925
| -2% | -$38.9K |
|
2012
Guardant Health
GH
$19.5B
| $1.94M | ﹤0.01% |
+18,994
| New | +$1.7M |
|
|
KLAR
2013
Klarna Group
KLAR
$6.56B
| $1.94M | ﹤0.01% |
67,051
+52,264
| +353% | +$1.79M |
|
2014
Dynatrace
DT
$12.1B
| $1.94M | ﹤0.01% |
44,681
-16,026
| -26% | -$747K |
|
2015
PUT
ProShares UltraShort Health Care
RXD
$3.25M
| $1.93M | ﹤0.01% |
27,650
+5,200
| +23% | +$102K |
|
2016
CALL
Huntsman Corp
HUN
$2.24B
| $1.93M | ﹤0.01% |
192,800
+20,700
| +12% | +$190K |
|
2017
CALL
Warrior Met Coal
HCC
$4.23B
| $1.92M | ﹤0.01% |
21,800
+16,400
| +304% | +$1.23M |
|
2018
CALL
Vista Energy
VIST
$7.75B
| $1.92M | ﹤0.01% |
39,500
-38,600
| -49% | -$1.74M |
|
2019
KeyCorp
KEY
$24.3B
| $1.92M | ﹤0.01% |
+93,023
| New | +$1.73M |
|
2020
Noble Corp
NE
$6.9B
| $1.92M | ﹤0.01% |
67,873
+24,215
| +55% | +$715K |
|
|
HOLX
2021
PUT
DELISTED
Hologic
HOLX
| $1.91M | ﹤0.01% |
25,700
-68,500
| -73% | -$5.01M |
|
2022
Steel Dynamics
STLD
$35.6B
| $1.91M | ﹤0.01% |
+11,295
| New | +$1.79M |
|
2023
CALL
Flutter Entertainment
FLUT
$17.6B
| $1.91M | ﹤0.01% |
8,900
-4,000
| -31% | -$900K |
|
2024
CALL
Remitly
RELY
$4.74B
| $1.91M | ﹤0.01% |
138,600
-221,100
| -61% | -$3.21M |
|
2025
PUT
Copart
CPRT
$25.9B
| $1.9M | ﹤0.01% |
48,600
-58,000
| -54% | -$2.4M |
|
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.