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 | |
|---|---|---|---|---|---|---|
7851
PUT
KT
KT
$8.95B
| $1.9K | ﹤0.01% |
100
-100
| -50% | -$1.86K |
|
7852
Rockwell Medical
RMTI
$27.6M
| $1.9K | ﹤0.01% |
227
+86
| +61% | +$868 |
|
|
AAT
7853
CALL
American Assets Trust
AAT
$1.48B
| $1.89K | ﹤0.01% |
+100
| New | +$1.93K |
|
7854
PUT
Century Therapeutics
IPSC
$370M
| $1.89K | ﹤0.01% |
+1,900
| New | +$1.16K |
|
7855
PUT
CareDx
CDNA
$1.85B
| $1.88K | ﹤0.01% |
100
-1,200
| -92% | -$20.1K |
|
|
LGO
7856
PUT
Largo
LGO
$60.5M
| $1.87K | ﹤0.01% |
+2,000
| New | +$2.37K |
|
7857
CALL
Backblaze
BLZE
$724M
| $1.86K | ﹤0.01% |
400
-300
| -43% | -$2.06K |
|
|
QPUX
7858
Defiance 2X Daily Long Pure Quantum ETF
QPUX
$29.5M
| $1.86K | ﹤0.01% |
+39
| New | +$3.96K |
|
7859
CALL
CVB Financial
CVBF
$4.02B
| $1.86K | ﹤0.01% |
100
| – | – |
|
7860
PUT
Nkarta
NKTX
$159M
| $1.85K | ﹤0.01% |
1,000
-19,800
| -95% | -$39.6K |
|
7861
CALL
Barings BDC
BBDC
$885M
| $1.84K | ﹤0.01% |
200
-5,800
| -97% | -$51.4K |
|
7862
CALL
Seer Inc
SEER
$118M
| $1.83K | ﹤0.01% |
1,000
| – | – |
|
7863
CALL
Simulations Plus
SLP
$371M
| $1.82K | ﹤0.01% |
100
-1,300
| -93% | -$22.8K |
|
7864
CALL
OceanFirst Financial
OCFC
$1.74B
| $1.79K | ﹤0.01% |
+100
| New | +$1.87K |
|
7865
CALL
Sunstone Hotel Investors
SHO
$2.19B
| $1.79K | ﹤0.01% |
200
| – | – |
|
7866
CALL
Colony Bankcorp
CBAN
$471M
| $1.78K | ﹤0.01% |
100
| – | – |
|
7867
PUT
The Oncology Institute
TOI
$495M
| $1.78K | ﹤0.01% |
+500
| New | +$1.85K |
|
|
GOOW
7868
Roundhill GOOGL WeeklyPay ETF
GOOW
$75.8M
| $1.77K | ﹤0.01% |
+25
| New | +$1.69K |
|
7869
Telecom Argentina
TEO
$5.86B
| $1.76K | ﹤0.01% |
152
-168
| -53% | -$1.8K |
|
7870
VanEck Video Gaming and eSports ETF
ESPO
$244M
| $1.76K | ﹤0.01% |
17
-30
| -64% | -$3.35K |
|
7871
CALL
Kelly Services Class A
KELYA
$560M
| $1.76K | ﹤0.01% |
200
-600
| -75% | -$6.1K |
|
|
VENU
7872
Venu Holding Corp
VENU
$133M
| $1.76K | ﹤0.01% |
+209
| New | +$2.32K |
|
7873
PUT
Lantronix
LTRX
$238M
| $1.76K | ﹤0.01% |
+300
| New | +$1.56K |
|
7874
Hyperfine
HYPR
$90.9M
| $1.75K | ﹤0.01% |
+1,787
| New | +$2.15K |
|
7875
PUT
AudioCodes
AUDC
$249M
| $1.75K | ﹤0.01% |
200
-12,300
| -98% | -$112K |
|
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.