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 | |
|---|---|---|---|---|---|---|
4826
iShares Core MSCI Emerging Markets ETF
IEMG
$149B
| $118K | ﹤0.01% |
1,757
-1,027
| -37% | -$68.9K |
|
4827
PUT
Black Hills Corp
BKH
$5.5B
| $118K | ﹤0.01% |
1,700
-1,800
| -51% | -$121K |
|
4828
PUT
DoubleVerify
DV
$1.69B
| $118K | ﹤0.01% |
10,300
-46,800
| -82% | -$516K |
|
4829
PUT
MSC Industrial Direct
MSM
$6.78B
| $118K | ﹤0.01% |
1,400
+1,100
| +367% | +$95.3K |
|
|
FJET
4830
PUT
Starfighters Space Inc
FJET
$176M
| $118K | ﹤0.01% |
+10,100
| New | +$140K |
|
|
BRSL
4831
CALL
Brightstar Lottery PLC
BRSL
$1.87B
| $118K | ﹤0.01% |
7,600
-3,000
| -28% | -$48.9K |
|
4832
PUT
Silicon Laboratories
SLAB
$7.15B
| $118K | ﹤0.01% |
900
+300
| +50% | +$39.4K |
|
4833
PUT
EnerSys
ENS
$6.74B
| $117K | ﹤0.01% |
+800
| New | +$107K |
|
|
MESO
4834
PUT
Mesoblast
MESO
$1.89B
| $117K | ﹤0.01% |
6,500
-18,000
| -73% | -$310K |
|
4835
CALL
Kaspi.kz JSC
KSPI
$16.9B
| $117K | ﹤0.01% |
1,500
-7,100
| -83% | -$537K |
|
4836
PUT
Matrix Service
MTRX
$320M
| $117K | ﹤0.01% |
10,000
| – | – |
|
4837
PUT
LivePerson
LPSN
$22M
| $117K | ﹤0.01% |
30,200
+28,173
| +1,390% | +$157K |
|
4838
PUT
Gossamer Bio
GOSS
$87.2M
| $117K | ﹤0.01% |
37,700
-9,500
| -20% | -$27.1K |
|
|
LENZ
4839
PUT
LENZ Therapeutics
LENZ
$181M
| $117K | ﹤0.01% |
7,300
-7,100
| -49% | -$207K |
|
4840
CALL
Edgewise Therapeutics
EWTX
$4.42B
| $117K | ﹤0.01% |
4,700
+2,700
| +135% | +$54.2K |
|
4841
CALL
Virtu Financial
VIRT
$5.15B
| $117K | ﹤0.01% |
3,500
-7,500
| -68% | -$256K |
|
4842
Ardmore Shipping
ASC
$703M
| $116K | ﹤0.01% |
10,997
+1,564
| +17% | +$18.6K |
|
4843
CALL
Genesco
GCO
$429M
| $116K | ﹤0.01% |
4,700
-300
| -6% | -$8.6K |
|
4844
Larimar Therapeutics
LRMR
$398M
| $116K | ﹤0.01% |
30,522
-184,940
| -86% | -$719K |
|
4845
PUT
Boston Omaha
BOC
$425M
| $116K | ﹤0.01% |
9,400
+100
| +1% | +$1.3K |
|
|
NEWP
4846
New Pacific Metals
NEWP
$881M
| $116K | ﹤0.01% |
33,100
+7,612
| +30% | +$20.8K |
|
4847
PUT
Arcutis Biotherapeutics
ARQT
$3.5B
| $116K | ﹤0.01% |
4,000
-1,600
| -29% | -$41K |
|
4848
CALL
Ituran Location and Control
ITRN
$1.1B
| $116K | ﹤0.01% |
2,700
+400
| +17% | +$15.7K |
|
|
CYPH
4849
PUT
Cypherpunk Technologies Inc
CYPH
$66.6M
| $116K | ﹤0.01% |
+100,100
| New | +$109K |
|
4850
CALL
National Grid
NGG
$80.8B
| $116K | ﹤0.01% |
1,500
-7,021
| -82% | -$528K |
|
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.