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 | |
|---|---|---|---|---|---|---|
226
PUT
First Solar
FSLR
$22.8B
| $64.8M | 0.04% |
247,900
-138,000
| -36% | -$34.8M |
|
227
PUT
CVS Health
CVS
$140B
| $64.7M | 0.04% |
814,900
+187,900
| +30% | +$14.8M |
|
228
PUT
Arista Networks
ANET
$222B
| $64.1M | 0.04% |
489,200
-140,400
| -22% | -$19.3M |
|
|
KFYP
229
PUT
DELISTED
KraneShares CICC China Leaders 100 Index ETF
KFYP
| $64M | 0.04% |
1,881,300
-877,000
| -32% | -$29.9M |
|
230
PUT
General Motors
GM
$74.7B
| $63.9M | 0.04% |
786,300
+96,000
| +14% | +$6.77M |
|
231
CALL
iShares Gold Trust
IAU
$64.5B
| $63.8M | 0.04% |
785,400
+267,700
| +52% | +$20.9M |
|
232
CALL
Lucid Motors
LCID
$2.79B
| $63.3M | 0.04% |
5,992,800
-886,000
| -13% | -$14.2M |
|
233
CALL
Intuitive Surgical
ISRG
$121B
| $63.1M | 0.04% |
111,500
+5,300
| +5% | +$2.82M |
|
234
PUT
GE Vernova
GEV
$269B
| $63.1M | 0.04% |
96,600
-52,700
| -35% | -$32.1M |
|
235
PUT
TeraWulf
WULF
$10.1B
| $63M | 0.04% |
5,481,600
+1,139,200
| +26% | +$15.3M |
|
236
CALL
AutoZone
AZO
$48.7B
| $62.1M | 0.04% |
18,300
-11,200
| -38% | -$42.3M |
|
237
CALL
Unity
U
$12.7B
| $62M | 0.03% |
1,403,700
-170,300
| -11% | -$6.94M |
|
238
CALL
Accenture
ACN
$85.9B
| $61.9M | 0.03% |
230,600
-8,100
| -3% | -$2.06M |
|
|
XYZ
239
CALL
Block Inc
XYZ
$46.2B
| $61.3M | 0.03% |
941,800
-317,700
| -25% | -$21.9M |
|
240
PUT
American Express
AXP
$238B
| $61.2M | 0.03% |
165,300
-41,800
| -20% | -$15M |
|
241
CALL
Datadog
DDOG
$88.3B
| $60.8M | 0.03% |
447,100
-50,100
| -10% | -$7.92M |
|
242
CALL
Globalstar
GSAT
$10.3B
| $60.6M | 0.03% |
993,000
+20,100
| +2% | +$1.11M |
|
243
CALL
Dell
DELL
$288B
| $60.6M | 0.03% |
481,400
-352,200
| -42% | -$49.6M |
|
|
244
CALL
CVS Health
CVS
$140B
| $60.4M | 0.03% |
761,400
-93,800
| -11% | -$7.39M |
|
245
State Street SPDR S&P 500 ETF Trust
SPY
$789B
| $59.7M | 0.03% |
87,518
-66,765
| -43% | -$45.1M |
|
246
CALL
Lockheed Martin
LMT
$119B
| $59.3M | 0.03% |
122,700
-54,300
| -31% | -$26M |
|
247
PUT
United Parcel Service
UPS
$99.1B
| $59.3M | 0.03% |
597,700
-182,700
| -23% | -$17.1M |
|
|
248
Western Digital
WDC
$195B
| $58.9M | 0.03% |
+341,762
| New | +$51.8M |
|
249
CALL
Trade Desk
TTD
$8.4B
| $58.7M | 0.03% |
1,545,800
-226,100
| -13% | -$10M |
|
250
CALL
Astera Labs
ALAB
$57.3B
| $58.3M | 0.03% |
350,300
-68,400
| -16% | -$11.4M |
|
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.