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 | Miscellaneous | 98.27% |
| 2 | Technology | 0.59% |
| 3 | Consumer Discretionary | 0.21% |
| 4 | Healthcare | 0.2% |
| 5 | Industrials | 0.18% |
| Name | Market Value | Portfolio Weight | Shares or Principal |
Change in Stake | Capital Flow | |
|---|---|---|---|---|---|---|
476
PUT
Dollar General
DG
$29.4B
| $25M | 0.01% |
188,000
+16,100
| +9% | +$1.8M |
|
477
PUT
Datadog
DDOG
$76.5B
| $24.9M | 0.01% |
183,400
-182,200
| -50% | -$28.8M |
|
478
PUT
Danaher
DHR
$146B
| $24.9M | 0.01% |
109,000
+59,600
| +121% | +$13.1M |
|
|
DOCU
479
PUT
DocuSign
DOCU
$13.1B
| $24.9M | 0.01% |
364,200
+76,200
| +26% | +$5.27M |
|
480
CALL
Microchip Technology
MCHP
$40.3B
| $24.8M | 0.01% |
389,200
-116,600
| -23% | -$7.19M |
|
481
PUT
Synopsys
SNPS
$75.5B
| $24.8M | 0.01% |
52,900
-10,700
| -17% | -$4.75M |
|
482
PUT
Lyft
LYFT
$6.33B
| $24.7M | 0.01% |
1,275,700
-311,300
| -20% | -$6.47M |
|
483
CALL
Hecla Mining
HL
$13.9B
| $24.7M | 0.01% |
1,284,900
-333,300
| -21% | -$5.09M |
|
484
CALL
Cleveland-Cliffs
CLF
$7.13B
| $24.6M | 0.01% |
1,853,200
+38,700
| +2% | +$489K |
|
485
Vertiv
VRT
$108B
| $24.6M | 0.01% |
151,799
+89,462
| +144% | +$15.5M |
|
486
CALL
Avis
CAR
$4.9B
| $24.6M | 0.01% |
191,600
-30,500
| -14% | -$4.26M |
|
487
CALL
Oscar Health
OSCR
$9.95B
| $24.5M | 0.01% |
1,707,700
+160,800
| +10% | +$2.78M |
|
488
PUT
Zscaler
ZS
$27.7B
| $24.5M | 0.01% |
109,000
+16,700
| +18% | +$4.71M |
|
489
CALL
Roku
ROKU
$23.1B
| $24.5M | 0.01% |
225,700
-35,400
| -14% | -$3.59M |
|
490
CALL
Eos Energy Enterprises
EOSE
$1.41B
| $24.3M | 0.01% |
2,119,300
-821,800
| -28% | -$11.8M |
|
|
SCIU
491
PUT
DELISTED
Global X Scientific Beta US ETF
SCIU
| $24.1M | 0.01% |
497,300
-30,500
| -6% | -$1.48M |
|
|
492
CALL
Dollar General
DG
$29.4B
| $24M | 0.01% |
180,900
-26,700
| -13% | -$2.98M |
|
|
UCD
493
CALL
DELISTED
PROSHARES ULTRA BLOOMBERG COMMODITY
UCD
| $24M | 0.01% |
232,900
+126,200
| +118% | +$13M |
|
494
PUT
Abbott
ABT
$187B
| $23.9M | 0.01% |
190,600
-49,600
| -21% | -$6.32M |
|
495
CALL
BigBear.ai
BBAI
$1.4B
| $23.8M | 0.01% |
4,409,300
+525,300
| +14% | +$3.43M |
|
496
PUT
Vale
VALE
$65B
| $23.8M | 0.01% |
1,826,100
-385,000
| -17% | -$4.68M |
|
497
PUT
GraniteShares Bloomberg Commodity Broad Strategy No K-1 ETF
COMB
$158M
| $23.7M | 0.01% |
521,000
-102,600
| -16% | -$2.31M |
|
498
CALL
Duke Energy
DUK
$93.7B
| $23.7M | 0.01% |
202,500
+4,800
| +2% | +$586K |
|
|
IPFF
499
PUT
DELISTED
iShares International Preferred Stock ETF
IPFF
| $23.7M | 0.01% |
397,600
-167,100
| -30% | -$9.96M |
|
500
CALL
Philip Morris
PM
$284B
| $23.7M | 0.01% |
147,700
-139,400
| -49% | -$21.6M |
|
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's Q4 2025 filing shows 1,476 new, 2,599 increased, 4,088 reduced and 2,184 closed positions. Its largest new stake was Western Digital: 341,762 shares worth $58.9M. The largest sale was NVIDIA, an estimated $262M.
By sector, the portfolio is most concentrated in Miscellaneous at 98% of assets, up from 98% a quarter earlier, followed by Technology and Consumer Discretionary.
- 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.