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 | |
|---|---|---|---|---|---|---|
3201
Direxion Daily NVDA Bull 2X ETF
NVDU
$530M
| $555K | ﹤0.01% |
+4,716
| New | +$592K |
|
3202
Ambarella
AMBA
$2.99B
| $554K | ﹤0.01% |
7,824
+2,534
| +48% | +$205K |
|
|
VOYG
3203
PUT
Voyager Technologies
VOYG
$1.56B
| $554K | ﹤0.01% |
21,200
-19,700
| -48% | -$534K |
|
3204
CALL
Vista Gold
VGZ
$253M
| $553K | ﹤0.01% |
280,900
+193,700
| +222% | +$374K |
|
3205
ARK 21Shares Bitcoin ETF
ARKB
$2.47B
| $553K | ﹤0.01% |
19,029
-168,239
| -90% | -$5.59M |
|
3206
PUT
Kodak
KODK
$788M
| $552K | ﹤0.01% |
65,300
-185,200
| -74% | -$1.38M |
|
3207
Sundial Growers
SNDL
$351M
| $552K | ﹤0.01% |
332,781
-60,775
| -15% | -$122K |
|
3208
CALL
Lightwave Logic
LWLG
$945M
| $552K | ﹤0.01% |
170,400
+67,000
| +65% | +$297K |
|
3209
PUT
Sterling Infrastructure
STRL
$19.5B
| $551K | ﹤0.01% |
1,800
-200
| -10% | -$68.9K |
|
3210
Monte Rosa Therapeutics
GLUE
$1.91B
| $551K | ﹤0.01% |
35,124
+2,011
| +6% | +$27.1K |
|
|
CCCX
3211
PUT
DELISTED
Churchill Capital Corp X
CCCX
| $551K | ﹤0.01% |
35,300
+35,200
| +35,200% | +$592K |
|
3212
ProShares UltraPro Short Dow 30
SDOW
$165M
| $550K | ﹤0.01% |
+17,221
| New | +$584K |
|
3213
CALL
Textron
TXT
$16.7B
| $549K | ﹤0.01% |
6,300
-52,600
| -89% | -$4.4M |
|
3214
PUT
Dana Inc
DAN
$2.93B
| $549K | ﹤0.01% |
23,100
+1,700
| +8% | +$36K |
|
3215
CALL
Aegon
AEG
$13.5B
| $548K | ﹤0.01% |
71,100
-86,600
| -55% | -$662K |
|
3216
CALL
Algoma Steel
ASTL
$463M
| $548K | ﹤0.01% |
133,600
-37,900
| -22% | -$151K |
|
3217
CALL
Vanda Pharmaceuticals
VNDA
$314M
| $548K | ﹤0.01% |
+62,100
| New | +$342K |
|
3218
MasTec
MTZ
$26.6B
| $547K | ﹤0.01% |
+2,516
| New | +$528K |
|
3219
PUT
Dover
DOV
$27.7B
| $547K | ﹤0.01% |
2,800
-1,200
| -30% | -$219K |
|
3220
PUT
Consolidated Edison
ED
$41.1B
| $546K | ﹤0.01% |
5,500
-2,600
| -32% | -$258K |
|
3221
CALL
Atlanta Braves Holdings Series B
BATRK
$3.25B
| $546K | ﹤0.01% |
13,800
+4,800
| +53% | +$190K |
|
3222
CALL
Mirum Pharmaceuticals
MIRM
$6.96B
| $545K | ﹤0.01% |
6,900
-2,300
| -25% | -$165K |
|
3223
Scholastic
SCHL
$769M
| $544K | ﹤0.01% |
18,372
-9,203
| -33% | -$264K |
|
|
ACB
3224
PUT
Aurora Cannabis
ACB
$170M
| $544K | ﹤0.01% |
135,200
-11,200
| -8% | -$54.8K |
|
3225
PUT
Phunware
PHUN
$43.1M
| $544K | ﹤0.01% |
294,000
+293,300
| +41,900% | +$682K |
|
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.