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 | |
|---|---|---|---|---|---|---|
|
THR
5751
CALL
DELISTED
Thermon Group Holdings
THR
| $44.6K | ﹤0.01% |
+1,200
| New | +$39.4K |
|
|
HUYA
5752
Huya Inc
HUYA
$563M
| $44.6K | ﹤0.01% |
+15,480
| New | +$45.4K |
|
5753
CALL
Brunswick
BC
$5.13B
| $44.5K | ﹤0.01% |
600
-6,800
| -92% | -$461K |
|
5754
CALL
Lantronix
LTRX
$240M
| $44.5K | ﹤0.01% |
+7,600
| New | +$39.5K |
|
|
RPC
5755
Ridgepost Capital
RPC
$949M
| $44.5K | ﹤0.01% |
4,538
+3,493
| +334% | +$35.4K |
|
5756
CALL
Herc Holdings
HRI
$5.02B
| $44.5K | ﹤0.01% |
300
-11,300
| -97% | -$1.55M |
|
|
TRON
5757
Tron Inc
TRON
$664M
| $44.5K | ﹤0.01% |
35,851
+19,727
| +122% | +$44.5K |
|
5758
CALL
Hubbell
HUBB
$25B
| $44.4K | ﹤0.01% |
100
-3,600
| -97% | -$1.58M |
|
|
YSG
5759
CALL
Yatsen Holding
YSG
$322M
| $44.3K | ﹤0.01% |
11,400
+2,100
| +23% | +$13.3K |
|
5760
CALL
Hexcel
HXL
$7.79B
| $44.3K | ﹤0.01% |
600
-1,000
| -63% | -$70.7K |
|
5761
PUT
Washington Trust Bancorp
WASH
$743M
| $44.3K | ﹤0.01% |
1,500
-4,800
| -76% | -$137K |
|
|
EMA
5762
CALL
Emera Inc
EMA
$16.5B
| $44.3K | ﹤0.01% |
900
| – | – |
|
5763
iShares Lithium Miners and Producers ETF
ILIT
$13.5M
| $44.3K | ﹤0.01% |
2,832
+51
| +2% | +$729 |
|
5764
AMC Global Media
AMCX
$492M
| $44.2K | ﹤0.01% |
4,643
-19,617
| -81% | -$165K |
|
5765
CALL
Larimar Therapeutics
LRMR
$397M
| $44.2K | ﹤0.01% |
11,600
-347,000
| -97% | -$1.35M |
|
5766
ProShares Ultra Yen
YCL
$33.2M
| $44.2K | ﹤0.01% |
2,317
+2,315
| +115,750% | +$46.1K |
|
5767
CALL
Mach Natural Resources
MNR
$2.28B
| $44.2K | ﹤0.01% |
+4,000
| New | +$48K |
|
5768
CALL
Plexus
PLXS
$6.72B
| $44.1K | ﹤0.01% |
+300
| New | +$44K |
|
|
DVS
5769
CALL
DELISTED
Dolly Varden Silver Corp
DVS
| $44.1K | ﹤0.01% |
10,000
+3,500
| +54% | +$15.4K |
|
5770
PUT
Webster Financial
WBS
$12.5B
| $44.1K | ﹤0.01% |
+700
| New | +$41.6K |
|
5771
PUT
UDR
UDR
$12.3B
| $44K | ﹤0.01% |
1,200
-2,700
| -69% | -$96K |
|
5772
CALL
MiMedx Group
MDXG
$602M
| $44K | ﹤0.01% |
6,500
-29,800
| -82% | -$209K |
|
5773
NerdWallet
NRDS
$592M
| $44K | ﹤0.01% |
+3,247
| New | +$42.5K |
|
5774
CALL
Full Truck Alliance
YMM
$9.85B
| $44K | ﹤0.01% |
4,100
-37,600
| -90% | -$451K |
|
5775
PUT
Cardlytics
CDLX
$21.7M
| $43.9K | ﹤0.01% |
3,820
-16,520
| -81% | -$255K |
|
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.