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 | |
|---|---|---|---|---|---|---|
6676
CALL
Mitek Systems
MITK
$754M
| $15.8K | ﹤0.01% |
1,500
+900
| +150% | +$8.5K |
|
6677
PUT
Goldgroup Mining Inc.
GORO
$157M
| $15.8K | ﹤0.01% |
19,100
-1,900
| -9% | -$1.51K |
|
6678
CALL
Telos
TLS
$332M
| $15.8K | ﹤0.01% |
3,100
-3,200
| -51% | -$20K |
|
6679
PUT
One Stop Systems
OSS
$303M
| $15.8K | ﹤0.01% |
2,200
-2,900
| -57% | -$17.1K |
|
6680
PUT
BJ's Restaurants
BJRI
$1.42B
| $15.8K | ﹤0.01% |
400
-7,800
| -95% | -$277K |
|
|
AVNS
6681
CALL
DELISTED
Avanos Medical
AVNS
| $15.7K | ﹤0.01% |
1,400
-25,300
| -95% | -$289K |
|
6682
PUT
AC Immune
ACIU
$223M
| $15.7K | ﹤0.01% |
+5,000
| New | +$15.8K |
|
6683
PUT
Arbe Robotics
ARBE
$80.3M
| $15.7K | ﹤0.01% |
13,300
-15,200
| -53% | -$25.1K |
|
6684
PUT
MGE Energy Inc
MGEE
$3B
| $15.7K | ﹤0.01% |
+200
| New | +$16.4K |
|
|
JFIN
6685
CALL
Jiayin Group
JFIN
$113M
| $15.7K | ﹤0.01% |
2,700
+2,100
| +350% | +$17.7K |
|
|
PPLI
6686
CALL
People Inc
PPLI
$3.09B
| $15.6K | ﹤0.01% |
400
-3,100
| -89% | -$109K |
|
6687
CALL
Avient
AVNT
$3.33B
| $15.6K | ﹤0.01% |
+500
| New | +$15.5K |
|
6688
ProShares UltraShort Financials
SKF
$10.3M
| $15.6K | ﹤0.01% |
614
+577
| +1,559% | +$15.7K |
|
6689
PUT
Kymera Therapeutics
KYMR
$8.51B
| $15.6K | ﹤0.01% |
+200
| New | +$13.5K |
|
6690
CALL
Pacira BioSciences
PCRX
$1.04B
| $15.5K | ﹤0.01% |
600
-600
| -50% | -$14.3K |
|
6691
Anixa Biosciences
ANIX
$116M
| $15.5K | ﹤0.01% |
4,965
-3,219
| -39% | -$13.2K |
|
6692
PUT
Insperity
NSP
$1.93B
| $15.5K | ﹤0.01% |
400
| – | – |
|
6693
PUT
SLR Investment Corp
SLRC
$686M
| $15.5K | ﹤0.01% |
1,000
+800
| +400% | +$12.2K |
|
|
TONX
6694
TON Strategy Co
TONX
$168M
| $15.5K | ﹤0.01% |
7,768
+2,817
| +57% | +$10.3K |
|
6695
CVB Financial
CVBF
$3.94B
| $15.4K | ﹤0.01% |
+830
| New | +$15.9K |
|
6696
CALL
Veru
VERU
$36M
| $15.4K | ﹤0.01% |
7,200
-58,300
| -89% | -$174K |
|
6697
PDF Solutions
PDFS
$1.93B
| $15.4K | ﹤0.01% |
+540
| New | +$14.9K |
|
6698
YieldMax AI Option Income Strategy ETF
AIYY
$26.9M
| $15.3K | ﹤0.01% |
883
+344
| +64% | +$7.56K |
|
|
BAND
6699
Bandwidth Inc
BAND
$1.26B
| $15.3K | ﹤0.01% |
993
-1,456
| -59% | -$22.1K |
|
|
BCPC
6700
CALL
Balchem Corp
BCPC
$5.38B
| $15.3K | ﹤0.01% |
+100
| New | +$15.3K |
|
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.