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 | |
|---|---|---|---|---|---|---|
651
CALL
MPLX
MPLX
$57.4B
| $15.2M | 0.01% |
284,600
-111,100
| -28% | -$5.79M |
|
652
CALL
SAP
SAP
$174B
| $15.2M | 0.01% |
62,500
+23,000
| +58% | +$5.86M |
|
653
CALL
GitLab
GTLB
$5.3B
| $15.2M | 0.01% |
404,100
+47,600
| +13% | +$2.06M |
|
654
PUT
Teradyne
TER
$57.8B
| $15.2M | 0.01% |
78,300
+25,500
| +48% | +$4.38M |
|
655
PUT
Diamondback Energy
FANG
$57.1B
| $15.2M | 0.01% |
100,800
-27,900
| -22% | -$4.12M |
|
656
CALL
Ferrari
RACE
$65.4B
| $15.1M | 0.01% |
40,900
+23,300
| +132% | +$9.32M |
|
657
PUT
Novartis
NVS
$291B
| $15M | 0.01% |
109,200
+3,200
| +3% | +$419K |
|
658
PUT
NRG Energy
NRG
$29.5B
| $15M | 0.01% |
94,400
-53,900
| -36% | -$8.92M |
|
|
659
CALL
Diamondback Energy
FANG
$57.1B
| $15M | 0.01% |
99,700
+45,500
| +84% | +$6.71M |
|
660
PUT
VanEck Durable High Dividend ETF
DURA
$38.5M
| $15M | 0.01% |
76,600
+41,600
| +119% | +$1.4M |
|
661
PUT
DraftKings
DKNG
$11.3B
| $15M | 0.01% |
434,600
-705,300
| -62% | -$23.2M |
|
662
PUT
BP
BP
$112B
| $14.9M | 0.01% |
430,200
-96,000
| -18% | -$3.37M |
|
663
PUT
QuantumScape Corp
QS
$3.61B
| $14.9M | 0.01% |
1,426,900
+263,800
| +23% | +$3.64M |
|
664
CALL
Enphase Energy
ENPH
$5.22B
| $14.9M | 0.01% |
463,800
-161,900
| -26% | -$5.24M |
|
665
PUT
Carrier Global
CARR
$56.6B
| $14.6M | 0.01% |
276,900
+137,900
| +99% | +$7.67M |
|
666
PUT
Best Buy
BBY
$18.4B
| $14.6M | 0.01% |
217,500
+61,100
| +39% | +$4.66M |
|
667
PUT
Lumen
LUMN
$6.9B
| $14.6M | 0.01% |
1,873,400
-1,060,000
| -36% | -$8.72M |
|
668
CALL
CSX Corp
CSX
$92.8B
| $14.5M | 0.01% |
400,600
-378,100
| -49% | -$13.5M |
|
669
PUT
eBay
EBAY
$49.3B
| $14.5M | 0.01% |
166,400
+4,100
| +3% | +$355K |
|
670
CALL
Expedia Group
EXPE
$31.3B
| $14.5M | 0.01% |
51,100
+1,300
| +3% | +$321K |
|
671
CALL
Coherent
COHR
$61.1B
| $14.4M | 0.01% |
78,100
-41,400
| -35% | -$6.19M |
|
672
CALL
Fortinet
FTNT
$114B
| $14.4M | 0.01% |
181,500
-115,700
| -39% | -$9.6M |
|
673
PUT
Oscar Health
OSCR
$8.89B
| $14.4M | 0.01% |
999,900
-1,189,200
| -54% | -$20.6M |
|
674
Nu Holdings
NU
$70.1B
| $14.4M | 0.01% |
858,285
+9,343
| +1% | +$150K |
|
675
CALL
Fluor
FLR
$7.21B
| $14.3M | 0.01% |
361,900
-37,500
| -9% | -$1.66M |
|
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.