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 | |
|---|---|---|---|---|---|---|
401
CALL
Affirm
AFRM
$24.8B
| $31.7M | 0.02% |
425,700
-211,200
| -33% | -$15.2M |
|
402
CALL
Snap
SNAP
$7.52B
| $31.6M | 0.02% |
3,918,500
-1,686,000
| -30% | -$13.3M |
|
403
PUT
Boston Scientific
BSX
$63.9B
| $31.5M | 0.02% |
330,400
-17,500
| -5% | -$1.72M |
|
404
CALL
Zoom
ZM
$25.2B
| $31.4M | 0.02% |
364,000
-68,600
| -16% | -$5.77M |
|
405
CALL
Lyft
LYFT
$5.57B
| $31.2M | 0.02% |
1,612,500
-1,064,000
| -40% | -$22.1M |
|
406
PUT
Mercado Libre
MELI
$91.2B
| $31M | 0.02% |
15,400
+4,100
| +36% | +$8.61M |
|
407
PUT
ConocoPhillips
COP
$145B
| $30.9M | 0.02% |
330,300
-37,000
| -10% | -$3.35M |
|
408
AST SpaceMobile
ASTS
$18.5B
| $30.7M | 0.02% |
422,850
-64,295
| -13% | -$4.59M |
|
409
UnitedHealth
UNH
$392B
| $30.6M | 0.02% |
92,725
-227,331
| -71% | -$77M |
|
410
PUT
Altria Group
MO
$121B
| $30.6M | 0.02% |
530,100
-236,000
| -31% | -$14.2M |
|
411
CALL
Constellation Brands
STZ
$22.6B
| $30.5M | 0.02% |
221,200
+56,600
| +34% | +$7.77M |
|
412
CALL
Union Pacific
UNP
$174B
| $30.5M | 0.02% |
131,700
-26,800
| -17% | -$6.12M |
|
413
CALL
Teradyne
TER
$57.8B
| $30.4M | 0.02% |
157,100
+12,600
| +9% | +$2.16M |
|
414
CALL
CleanSpark
CLSK
$3.93B
| $30.4M | 0.02% |
3,000,200
-490,000
| -14% | -$7.34M |
|
415
CALL
Applied Digital
APLD
$8.6B
| $30.1M | 0.02% |
1,229,400
-599,900
| -33% | -$17.3M |
|
416
CALL
Zscaler
ZS
$23B
| $30M | 0.02% |
133,300
+18,200
| +16% | +$5.14M |
|
417
CALL
First Majestic Silver
AG
$8.55B
| $29.9M | 0.02% |
1,797,600
+64,200
| +4% | +$892K |
|
418
CALL
Halliburton
HAL
$27.6B
| $29.9M | 0.02% |
1,057,200
-63,700
| -6% | -$1.68M |
|
419
CALL
Energy Fuels
UUUU
$3.08B
| $29.9M | 0.02% |
2,053,800
+1,123,400
| +121% | +$19.1M |
|
|
CFLT
420
CALL
DELISTED
Confluent
CFLT
| $29.8M | 0.02% |
986,200
-767,400
| -44% | -$18.8M |
|
421
CALL
DoorDash
DASH
$77.4B
| $29.7M | 0.02% |
131,300
-32,900
| -20% | -$7.72M |
|
422
CALL
Celsius Holdings
CELH
$7.28B
| $29.5M | 0.02% |
645,900
-304,500
| -32% | -$15.3M |
|
423
CALL
Duolingo
DUOL
$5.57B
| $29.5M | 0.02% |
167,900
+68,800
| +69% | +$16.2M |
|
424
CALL
QuantumScape Corp
QS
$3.61B
| $29.2M | 0.02% |
2,806,400
-190,400
| -6% | -$2.62M |
|
425
PUT
3M
MMM
$89.1B
| $29.2M | 0.02% |
219,300
-39,400
| -15% | -$6.44M |
|
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.