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 | |
|---|---|---|---|---|---|---|
5026
Talphera
TLPH
$66.4M
| $97.8K | ﹤0.01% |
85,799
+84,572
| +6,893% | +$102K |
|
5027
Ocugen
OCGN
$416M
| $97.7K | ﹤0.01% |
72,385
+64,183
| +783% | +$91.4K |
|
5028
CALL
Lexicon Pharmaceuticals
LXRX
$1.03B
| $97.6K | ﹤0.01% |
84,900
-48,500
| -36% | -$66.6K |
|
5029
PUT
Pilgrim's Pride
PPC
$6.51B
| $97.5K | ﹤0.01% |
2,500
-9,900
| -80% | -$381K |
|
5030
Xponential Fitness
XPOF
$273M
| $97.3K | ﹤0.01% |
+11,822
| New | +$84K |
|
5031
CALL
Kilroy Realty
KRC
$4.52B
| $97.2K | ﹤0.01% |
2,600
-300
| -10% | -$12.3K |
|
|
LAR
5032
PUT
Lithium Argentina AG
LAR
$985M
| $97.1K | ﹤0.01% |
17,400
-2,100
| -11% | -$9.97K |
|
5033
DiaMedica Therapeutics
DMAC
$342M
| $96.6K | ﹤0.01% |
12,132
+10,056
| +484% | +$75.2K |
|
|
EFC
5034
CALL
Ellington Financial
EFC
$1.67B
| $96.4K | ﹤0.01% |
7,100
-2,700
| -28% | -$36.7K |
|
|
RAPT
5035
DELISTED
RAPT Therapeutics
RAPT
| $96.4K | ﹤0.01% |
+2,846
| New | +$88.4K |
|
|
MSB
5036
CALL
Mesabi Trust
MSB
$289M
| $96.3K | ﹤0.01% |
2,500
+2,300
| +1,150% | +$77.9K |
|
5037
PUT
Clearway Energy Class C
CWEN
$4.94B
| $96.3K | ﹤0.01% |
2,900
+2,600
| +867% | +$86.5K |
|
5038
CALL
GrafTech
EAF
$175M
| $96.2K | ﹤0.01% |
6,200
-99,500
| -94% | -$1.51M |
|
5039
CALL
Pyxis Oncology
PYXS
$168M
| $95.9K | ﹤0.01% |
83,400
+64,700
| +346% | +$228K |
|
5040
PUT
Tennant Co
TNC
$1.43B
| $95.8K | ﹤0.01% |
1,300
| – | – |
|
5041
CALL
Middlesex Water
MSEX
$1.07B
| $95.8K | ﹤0.01% |
1,900
+900
| +90% | +$48.4K |
|
|
SOFX
5042
Defiance Daily Target 2X Long SOFI ETF
SOFX
$69.8M
| $95.8K | ﹤0.01% |
3,372
-1,476
| -30% | -$57.8K |
|
5043
CALL
AC Immune
ACIU
$223M
| $95.8K | ﹤0.01% |
30,500
+23,900
| +362% | +$75.4K |
|
5044
KBR
KBR
$4.64B
| $95.7K | ﹤0.01% |
2,381
+1,616
| +211% | +$69.3K |
|
5045
PUT
Plains GP Holdings
PAGP
$5.21B
| $95.7K | ﹤0.01% |
5,000
-29,800
| -86% | -$537K |
|
5046
PUT
Edgewell Personal Care
EPC
$1.25B
| $95.5K | ﹤0.01% |
5,600
+5,400
| +2,700% | +$99.9K |
|
|
SMCX
5047
Defiance Daily Target 2X Long SMCI ETF
SMCX
$154M
| $95.5K | ﹤0.01% |
+4,187
| New | +$233K |
|
|
WTMY
5048
PUT
WisdomTree High Income Laddered Municipal Fund
WTMY
$4.99M
| $95.3K | ﹤0.01% |
1,600
+400
| +33% | +$10.2K |
|
5049
PUT
Methanex
MEOH
$4.3B
| $95.3K | ﹤0.01% |
2,400
-18,000
| -88% | -$670K |
|
5050
Triumph Financial Inc
TFIN
$1.81B
| $95.3K | ﹤0.01% |
1,522
+1,508
| +10,771% | +$84.5K |
|
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.