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 | |
|---|---|---|---|---|---|---|
3276
Jazz Pharmaceuticals
JAZZ
$16B
| $517K | ﹤0.01% |
3,042
+2,151
| +241% | +$330K |
|
3277
Alight
ALIT
$520M
| $516K | ﹤0.01% |
13,240
+5,821
| +78% | +$290K |
|
3278
PUT
Corteva
CTVA
$58.6B
| $516K | ﹤0.01% |
7,700
-38,000
| -83% | -$2.46M |
|
3279
PUT
Verisk Analytics
VRSK
$27.1B
| $514K | ﹤0.01% |
+2,300
| New | +$519K |
|
3280
CALL
Editas Medicine
EDIT
$411M
| $514K | ﹤0.01% |
250,900
-16,800
| -6% | -$48.5K |
|
3281
PUT
Microvast
MVST
$267M
| $513K | ﹤0.01% |
183,300
-54,500
| -23% | -$228K |
|
3282
CALL
BJ's Restaurants
BJRI
$1.45B
| $512K | ﹤0.01% |
13,000
+10,900
| +519% | +$387K |
|
3283
PUT
AtaiBeckley Inc
ATAI
$2.65B
| $512K | ﹤0.01% |
125,200
-16,200
| -11% | -$76.4K |
|
3284
Star Bulk Carriers
SBLK
$3.02B
| $512K | ﹤0.01% |
26,642
-8,016
| -23% | -$150K |
|
3285
CALL
Power Integrations
POWI
$3.53B
| $512K | ﹤0.01% |
14,400
+14,100
| +4,700% | +$534K |
|
3286
CALL
Agios Pharmaceuticals
AGIO
$2.2B
| $512K | ﹤0.01% |
18,800
-24,300
| -56% | -$853K |
|
3287
Energy Vault
NRGV
$531M
| $510K | ﹤0.01% |
110,721
-62,098
| -36% | -$238K |
|
3288
Avery Dennison
AVY
$12.5B
| $510K | ﹤0.01% |
+2,805
| New | +$485K |
|
3289
CALL
ThredUp
TDUP
$756M
| $510K | ﹤0.01% |
79,800
+3,700
| +5% | +$29.9K |
|
3290
Defiance Quantum ETF
QTUM
$5.21B
| $509K | ﹤0.01% |
+4,646
| New | +$512K |
|
3291
Autodesk
ADSK
$47.7B
| $509K | ﹤0.01% |
1,721
+1,541
| +856% | +$466K |
|
3292
PUT
Everest Group
EG
$15.4B
| $509K | ﹤0.01% |
1,500
+100
| +7% | +$33K |
|
|
DEFT
3293
CALL
Defi Technologies
DEFT
$166M
| $507K | ﹤0.01% |
671,300
+173,000
| +35% | +$265K |
|
3294
PUT
Iridium Communications
IRDM
$4.87B
| $504K | ﹤0.01% |
29,000
-900
| -3% | -$15.9K |
|
3295
PUT
Odyssey Marine Exploration
OMEX
$41.5M
| $504K | ﹤0.01% |
256,900
+149,600
| +139% | +$346K |
|
3296
PUT
Prime Medicine
PRME
$544M
| $503K | ﹤0.01% |
144,900
+27,800
| +24% | +$124K |
|
3297
Immunome
IMNM
$2.56B
| $503K | ﹤0.01% |
23,401
-38,292
| -62% | -$672K |
|
|
PLG
3298
CALL
Platinum Group Metals
PLG
$162M
| $502K | ﹤0.01% |
212,700
+170,000
| +398% | +$410K |
|
3299
ASP Isotopes
ASPI
$510M
| $501K | ﹤0.01% |
93,716
+80,319
| +600% | +$639K |
|
3300
PUT
Magna International
MGA
$18.3B
| $501K | ﹤0.01% |
9,400
-99,900
| -91% | -$4.88M |
|
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.