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 | |
|---|---|---|---|---|---|---|
576
PUT
Microchip Technology
MCHP
$46.2B
| $18.8M | 0.01% |
294,400
-110,100
| -27% | -$6.79M |
|
577
PUT
T-Mobile US
TMUS
$207B
| $18.7M | 0.01% |
92,100
-32,200
| -26% | -$6.83M |
|
|
GLXY
578
CALL
Galaxy Digital Inc
GLXY
$4.75B
| $18.7M | 0.01% |
834,100
+285,300
| +52% | +$8.84M |
|
579
PUT
Cipher Digital
CIFR
$10B
| $18.6M | 0.01% |
1,258,800
-1,810,500
| -59% | -$32M |
|
580
PUT
Five Below
FIVE
$11.3B
| $18.6M | 0.01% |
98,600
| – | – |
|
581
PUT
Amgen
AMGN
$198B
| $18.5M | 0.01% |
56,500
-65,400
| -54% | -$20.7M |
|
582
CALL
KLA
KLAC
$280B
| $18.5M | 0.01% |
152,000
+21,000
| +16% | +$2.46M |
|
583
CALL
Blackrock
BLK
$164B
| $18.4M | 0.01% |
17,200
+4,800
| +39% | +$5.25M |
|
584
CALL
On Holding
ONON
$12.2B
| $18.4M | 0.01% |
395,800
-112,400
| -22% | -$4.84M |
|
585
SLB Ltd
SLB
$71.3B
| $18.4M | 0.01% |
479,075
+146,758
| +44% | +$5.32M |
|
586
PUT
HCA Healthcare
HCA
$82.5B
| $18.3M | 0.01% |
39,300
-1,500
| -4% | -$696K |
|
587
CALL
US Bancorp Series B Preferred Stock
USB.PRH
$747M
| $18.3M | 0.01% |
343,600
-212,100
| -38% | -$3.97M |
|
588
PUT
Phillips 66
PSX
$84.8B
| $18.3M | 0.01% |
141,600
-28,900
| -17% | -$3.89M |
|
589
CALL
Vanguard Consumer Discretionary ETF
VCR
$6.07B
| $18.2M | 0.01% |
26,800
-13,400
| -33% | -$5.24M |
|
590
PUT
British American Tobacco
BTI
$134B
| $18.1M | 0.01% |
319,400
-32,800
| -9% | -$1.79M |
|
591
CALL
Spotify
SPOT
$97.5B
| $18.1M | 0.01% |
31,100
-64,900
| -68% | -$40.6M |
|
592
PUT
GameStop
GME
$9.69B
| $18M | 0.01% |
1,462,200
-176,200
| -11% | -$3.95M |
|
|
HUT
593
CALL
Hut 8
HUT
$12.4B
| $18M | 0.01% |
395,700
-288,200
| -42% | -$12.7M |
|
594
PUT
Applied Optoelectronics
AAOI
$8.87B
| $18M | 0.01% |
515,100
+206,700
| +67% | +$6.17M |
|
595
PUT
Atlassian
TEAM
$21.7B
| $17.9M | 0.01% |
110,500
-30,400
| -22% | -$4.77M |
|
596
CALL
Ondas Inc
ONDS
$4.56B
| $17.9M | 0.01% |
1,835,200
-152,300
| -8% | -$1.22M |
|
597
PUT
Valero Energy
VLO
$92.3B
| $17.9M | 0.01% |
110,000
-160,300
| -59% | -$27.2M |
|
598
CALL
Vertex Pharmaceuticals
VRTX
$120B
| $17.9M | 0.01% |
39,400
-1,800
| -4% | -$776K |
|
|
599
CALL
Valero Energy
VLO
$92.3B
| $17.9M | 0.01% |
109,700
-6,600
| -6% | -$1.12M |
|
600
CALL
Deere & Co
DE
$164B
| $17.8M | 0.01% |
38,300
-3,400
| -8% | -$1.6M |
|
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.