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 | |
|---|---|---|---|---|---|---|
6726
CALL
Gibraltar Industries
ROCK
$1.25B
| $14.8K | ﹤0.01% |
+300
| New | +$17.2K |
|
6727
PUT
Gyre Therapeutics
GYRE
$641M
| $14.8K | ﹤0.01% |
+2,100
| New | +$16.2K |
|
6728
Torrid Holdings
CURV
$254M
| $14.8K | ﹤0.01% |
15,099
+9,048
| +150% | +$11.6K |
|
6729
PUT
Ichor Holdings
ICHR
$2.62B
| $14.7K | ﹤0.01% |
800
+700
| +700% | +$13K |
|
6730
CALL
Boise Cascade
BCC
$2.69B
| $14.7K | ﹤0.01% |
200
+100
| +100% | +$7.29K |
|
6731
PDS Biotechnology
PDSB
$38.4M
| $14.7K | ﹤0.01% |
19,106
+6,701
| +54% | +$6.04K |
|
6732
PUT
Plexus
PLXS
$6.72B
| $14.7K | ﹤0.01% |
+100
| New | +$14.7K |
|
6733
PUT
ThredUp
TDUP
$746M
| $14.7K | ﹤0.01% |
2,300
-9,900
| -81% | -$80.1K |
|
6734
CALL
Traeger
COOK
$178M
| $14.7K | ﹤0.01% |
272
-290
| -52% | -$14.1K |
|
6735
Noodles & Co
NDLS
$111M
| $14.7K | ﹤0.01% |
2,598
+439
| +20% | +$2.49K |
|
|
DSL
6736
CALL
DoubleLine Income Solutions Fund
DSL
$1.22B
| $14.7K | ﹤0.01% |
1,300
-8,500
| -87% | -$98.3K |
|
6737
CALL
DXC Technology
DXC
$1.82B
| $14.7K | ﹤0.01% |
1,000
-2,100
| -68% | -$28.9K |
|
|
SIFY
6738
PUT
Sify Technologies
SIFY
$1.06B
| $14.6K | ﹤0.01% |
1,200
+1,000
| +500% | +$12.2K |
|
6739
CALL
Mercury Systems
MRCY
$5.83B
| $14.6K | ﹤0.01% |
200
| – | – |
|
6740
PUT
MGP Ingredients
MGPI
$379M
| $14.6K | ﹤0.01% |
600
-1,900
| -76% | -$46.3K |
|
6741
Horizon Technology Finance
HRZN
$295M
| $14.6K | ﹤0.01% |
2,260
-817
| -27% | -$5.22K |
|
6742
Enanta Pharmaceuticals
ENTA
$366M
| $14.5K | ﹤0.01% |
922
+75
| +9% | +$953 |
|
6743
Roundhill S&P 500 0DTE Covered Call Strategy ETF
XDTE
$340M
| $14.5K | ﹤0.01% |
+365
| New | +$15.8K |
|
6744
PUT
Sylvamo
SLVM
$1.49B
| $14.4K | ﹤0.01% |
300
-700
| -70% | -$31.9K |
|
6745
CALL
Ryanair
RYAAY
$30.4B
| $14.4K | ﹤0.01% |
200
-4,900
| -96% | -$319K |
|
6746
CALL
Regenxbio
RGNX
$620M
| $14.4K | ﹤0.01% |
1,000
-14,000
| -93% | -$174K |
|
|
CGAU
6747
PUT
Centerra Gold
CGAU
$3.36B
| $14.4K | ﹤0.01% |
1,000
-8,100
| -89% | -$101K |
|
6748
Crexendo
CXDO
$223M
| $14.4K | ﹤0.01% |
2,221
+2,213
| +27,663% | +$14.5K |
|
6749
Aura Biosciences
AURA
$725M
| $14.4K | ﹤0.01% |
+2,634
| New | +$15.6K |
|
6750
Nabors Industries
NBR
$1.27B
| $14.3K | ﹤0.01% |
264
-2,066
| -89% | -$101K |
|
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.