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 | |
|---|---|---|---|---|---|---|
1376
Cameco
CCJ
$38.3B
| $4.4M | ﹤0.01% |
48,092
+37,490
| +354% | +$3.38M |
|
1377
CALL
Comfort Systems
FIX
$61B
| $4.39M | ﹤0.01% |
4,700
+3,900
| +488% | +$3.6M |
|
1378
ACM Research
ACMR
$5.83B
| $4.38M | ﹤0.01% |
110,952
+35,934
| +48% | +$1.34M |
|
1379
PUT
KB Home
KBH
$3.48B
| $4.37M | ﹤0.01% |
77,500
-18,200
| -19% | -$1.12M |
|
1380
CALL
ArcelorMittal
MT
$50.4B
| $4.36M | ﹤0.01% |
95,600
-195,900
| -67% | -$8.05M |
|
1381
PUT
Coupang
CPNG
$27.8B
| $4.35M | ﹤0.01% |
184,400
-131,600
| -42% | -$3.74M |
|
1382
PUT
Janus Henderson Small Cap Growth Alpha ETF
JSML
$366M
| $4.35M | ﹤0.01% |
91,100
+40,600
| +80% | +$3.02M |
|
1383
CALL
Viatris
VTRS
$20.1B
| $4.34M | ﹤0.01% |
348,900
+77,500
| +29% | +$836K |
|
1384
PUT
Cboe Global Markets
CBOE
$29.8B
| $4.34M | ﹤0.01% |
17,300
-4,200
| -20% | -$1.04M |
|
1385
CALL
SharkNinja
SN
$21B
| $4.34M | ﹤0.01% |
38,800
-16,200
| -29% | -$1.6M |
|
1386
CALL
Simon Property Group
SPG
$74.5B
| $4.33M | ﹤0.01% |
23,400
-9,700
| -29% | -$1.76M |
|
1387
CALL
Dynatrace
DT
$12.1B
| $4.32M | ﹤0.01% |
99,600
+33,500
| +51% | +$1.56M |
|
1388
CALL
Elastic
ESTC
$6.1B
| $4.32M | ﹤0.01% |
57,200
+7,100
| +14% | +$579K |
|
1389
Centrus Energy
LEU
$3.22B
| $4.31M | ﹤0.01% |
17,758
+16,737
| +1,639% | +$5.05M |
|
1390
CALL
OneMain Financial
OMF
$6.9B
| $4.31M | ﹤0.01% |
63,800
+26,700
| +72% | +$1.62M |
|
1391
CALL
Sherwin-Williams
SHW
$78.3B
| $4.31M | ﹤0.01% |
13,300
+1,300
| +11% | +$435K |
|
1392
PUT
Lamb Weston
LW
$6.85B
| $4.3M | ﹤0.01% |
102,600
-174,100
| -63% | -$10.2M |
|
1393
PUT
Planet Labs
PL
$7.3B
| $4.3M | ﹤0.01% |
217,800
-178,300
| -45% | -$2.56M |
|
1394
PUT
SSR Mining
SSRM
$5.57B
| $4.29M | ﹤0.01% |
195,700
-5,600
| -3% | -$125K |
|
1395
CALL
Enovix
ENVX
$862M
| $4.29M | ﹤0.01% |
586,700
+87,000
| +17% | +$843K |
|
1396
PUT
Cummins
CMI
$91.7B
| $4.29M | ﹤0.01% |
8,400
+4,300
| +105% | +$2.01M |
|
1397
CALL
Regions Financial
RF
$26.3B
| $4.29M | ﹤0.01% |
158,200
-28,200
| -15% | -$720K |
|
|
AMTM
1398
CALL
Amentum Holdings
AMTM
$5.51B
| $4.28M | ﹤0.01% |
147,700
+56,900
| +63% | +$1.45M |
|
1399
Magnite
MGNI
$2.65B
| $4.27M | ﹤0.01% |
263,362
+146,317
| +125% | +$2.43M |
|
1400
CALL
Universal Health Services
UHS
$9.43B
| $4.27M | ﹤0.01% |
19,600
+18,900
| +2,700% | +$4.18M |
|
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.