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 | |
|---|---|---|---|---|---|---|
3351
PUT
Vermilion Energy
VET
$1.58B
| $477K | ﹤0.01% |
57,200
-5,600
| -9% | -$46.2K |
|
3352
Adient
ADNT
$1.69B
| $477K | ﹤0.01% |
24,870
-5,436
| -18% | -$114K |
|
3353
PUT
BCE
BCE
$20.3B
| $476K | ﹤0.01% |
20,000
-77,000
| -79% | -$1.79M |
|
3354
CALL
Commault Systems
CVLT
$5.12B
| $476K | ﹤0.01% |
3,800
+2,700
| +245% | +$380K |
|
3355
CALL
Vera Therapeutics
VERA
$2.42B
| $476K | ﹤0.01% |
9,400
+6,200
| +194% | +$220K |
|
3356
CALL
Galectin Therapeutics
GALT
$216M
| $476K | ﹤0.01% |
114,400
+96,400
| +536% | +$508K |
|
3357
CALL
Biomea Fusion
BMEA
$88.2M
| $475K | ﹤0.01% |
383,200
+228,000
| +147% | +$319K |
|
3358
PAR Technology
PAR
$717M
| $475K | ﹤0.01% |
13,087
+8,468
| +183% | +$306K |
|
3359
PUT
Center Bancorp
CNOB
$1.68B
| $475K | ﹤0.01% |
18,100
-300
| -2% | -$7.6K |
|
3360
CALL
Nomad Foods
NOMD
$1.72B
| $474K | ﹤0.01% |
37,900
+37,600
| +12,533% | +$459K |
|
3361
PUT
DuPont de Nemours
DD
$19.2B
| $474K | ﹤0.01% |
25,433
-36,229
| -59% | -$4.08M |
|
3362
Elbit Systems
ESLT
$38.3B
| $474K | ﹤0.01% |
820
+666
| +432% | +$334K |
|
3363
Vanguard Mega Cap 300 Index ETF
MGC
$9.9B
| $473K | ﹤0.01% |
+1,885
| New | +$469K |
|
3364
ProShares UltraShort QQQ
QID
$290M
| $471K | ﹤0.01% |
23,339
+22,106
| +1,793% | +$455K |
|
3365
CALL
Corsair Gaming
CRSR
$1.14B
| $471K | ﹤0.01% |
79,300
-53,700
| -40% | -$373K |
|
|
RAL
3366
Ralliant Corp
RAL
$7.59B
| $471K | ﹤0.01% |
+9,245
| New | +$433K |
|
3367
CALL
Fossil Group
FOSL
$252M
| $470K | ﹤0.01% |
125,100
+115,100
| +1,151% | +$325K |
|
3368
Costamare
CMRE
$1.86B
| $469K | ﹤0.01% |
+29,717
| New | +$411K |
|
|
XNET
3369
CALL
Xunlei
XNET
$332M
| $469K | ﹤0.01% |
66,100
-135,900
| -67% | -$1.09M |
|
3370
CALL
ALPS REIT Dividend Dogs ETF
RDOG
$11.7M
| $465K | ﹤0.01% |
9,900
-19,600
| -66% | -$705K |
|
3371
CALL
Aaon
AAON
$7.84B
| $465K | ﹤0.01% |
6,100
-11,100
| -65% | -$1.03M |
|
3372
Fox Class B
FOX
$21.8B
| $465K | ﹤0.01% |
7,160
+1,760
| +33% | +$103K |
|
3373
CALL
Haemonetics
HAE
$3.77B
| $465K | ﹤0.01% |
5,800
+100
| +2% | +$6.72K |
|
3374
CALL
Host Hotels & Resorts
HST
$17B
| $465K | ﹤0.01% |
26,200
-47,400
| -64% | -$818K |
|
|
THR
3375
DELISTED
Thermon Group Holdings
THR
| $464K | ﹤0.01% |
12,492
+11,799
| +1,703% | +$387K |
|
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.