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 | |
|---|---|---|---|---|---|---|
3776
PUT
Revvity
RVTY
$12.4B
| $310K | ﹤0.01% |
3,200
-1,900
| -37% | -$182K |
|
3777
CALL
Sunoco
SUN
$14.4B
| $309K | ﹤0.01% |
5,900
+4,400
| +293% | +$232K |
|
3778
PUT
Ingersoll Rand
IR
$33.9B
| $309K | ﹤0.01% |
3,900
-2,300
| -37% | -$182K |
|
|
SUIG
3779
CALL
Sui Group Holdings
SUIG
$73M
| $309K | ﹤0.01% |
184,800
+35,500
| +24% | +$91.8K |
|
3780
CALL
Porch Group
PRCH
$1.38B
| $309K | ﹤0.01% |
33,800
+3,400
| +11% | +$40.9K |
|
3781
PUT
Camtek
CAMT
$6.53B
| $308K | ﹤0.01% |
2,900
-2,800
| -49% | -$315K |
|
|
XXI
3782
Twenty One Capital Inc
XXI
$1.53B
| $308K | ﹤0.01% |
+35,192
| New | +$367K |
|
3783
Advanced Drainage Systems
WMS
$11.1B
| $308K | ﹤0.01% |
2,126
+1,664
| +360% | +$241K |
|
3784
CALL
FNB Corp
FNB
$6.81B
| $308K | ﹤0.01% |
18,000
-3,600
| -17% | -$58.8K |
|
3785
PUT
DXC Technology
DXC
$1.76B
| $308K | ﹤0.01% |
21,000
+100
| +0.5% | +$1.38K |
|
3786
PUT
Genuine Parts
GPC
$17.9B
| $307K | ﹤0.01% |
2,500
-1,100
| -31% | -$142K |
|
3787
CALL
ProShares UltraShort Industrials
SIJ
$5.73M
| $307K | ﹤0.01% |
2,150
| – | – |
|
3788
Royal Gold
RGLD
$16.6B
| $307K | ﹤0.01% |
1,379
-11,904
| -90% | -$2.36M |
|
|
TXNM
3789
CALL
TXNM Energy Inc
TXNM
$6.43B
| $306K | ﹤0.01% |
5,200
+4,800
| +1,200% | +$277K |
|
3790
PUT
Arvinas
ARVN
$529M
| $306K | ﹤0.01% |
25,800
-197,100
| -88% | -$2.15M |
|
3791
Ouster
OUST
$2.28B
| $306K | ﹤0.01% |
14,133
-66,317
| -82% | -$1.75M |
|
3792
ClearPoint Neuro
CLPT
$436M
| $305K | ﹤0.01% |
22,323
-6,777
| -23% | -$126K |
|
3793
Dana Inc
DAN
$2.95B
| $305K | ﹤0.01% |
+12,850
| New | +$272K |
|
3794
CALL
Stoke Therapeutics
STOK
$1.83B
| $305K | ﹤0.01% |
9,600
+7,600
| +380% | +$228K |
|
3795
CALL
Gen Digital
GEN
$16.5B
| $305K | ﹤0.01% |
+11,200
| New | +$301K |
|
3796
CALL
Protara Therapeutics
TARA
$221M
| $304K | ﹤0.01% |
57,100
+56,000
| +5,091% | +$311K |
|
3797
Algoma Steel
ASTL
$463M
| $304K | ﹤0.01% |
+74,128
| New | +$295K |
|
3798
Tradeweb Markets
TW
$22.2B
| $304K | ﹤0.01% |
2,824
-12,700
| -82% | -$1.36M |
|
3799
CALL
Janux Therapeutics
JANX
$915M
| $304K | ﹤0.01% |
22,000
+21,900
| +21,900% | +$515K |
|
|
FOLD
3800
PUT
DELISTED
Amicus Therapeutics
FOLD
| $303K | ﹤0.01% |
21,300
-10,800
| -34% | -$106K |
|
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.