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 | |
|---|---|---|---|---|---|---|
626
CALL
General Dynamics
GD
$101B
| $16.3M | 0.01% |
48,500
+600
| +1% | +$205K |
|
627
PUT
Fair Isaac
FICO
$28.3B
| $16.2M | 0.01% |
9,600
-2,300
| -19% | -$3.96M |
|
628
CALL
The GEO Group
GEO
$4.19B
| $16.2M | 0.01% |
1,006,700
+75,500
| +8% | +$1.26M |
|
629
PUT
ON Semiconductor
ON
$35.9B
| $16.2M | 0.01% |
298,900
-220,800
| -42% | -$11.3M |
|
630
CALL
Grab
GRAB
$13.7B
| $16.1M | 0.01% |
3,234,500
-508,100
| -14% | -$2.81M |
|
631
CALL
Kinder Morgan
KMI
$72.3B
| $16.1M | 0.01% |
586,400
-183,800
| -24% | -$4.97M |
|
632
PUT
PG&E
PCG
$39.9B
| $16M | 0.01% |
997,200
-1,363,300
| -58% | -$21.8M |
|
633
PUT
Union Pacific
UNP
$174B
| $15.9M | 0.01% |
68,600
-18,300
| -21% | -$4.18M |
|
634
CALL
Antero Resources
AR
$10.9B
| $15.8M | 0.01% |
458,800
+320,000
| +231% | +$10.8M |
|
635
Constellation Energy
CEG
$98.2B
| $15.8M | 0.01% |
44,711
+43,501
| +3,595% | +$15.8M |
|
|
ECHO
636
EchoStar
ECHO
$26.7B
| $15.7M | 0.01% |
144,099
+49,813
| +53% | +$4.06M |
|
|
SNDK
637
Sandisk
SNDK
$237B
| $15.6M | 0.01% |
+65,895
| New | +$13.2M |
|
638
CALL
Keurig Dr Pepper
KDP
$41.1B
| $15.5M | 0.01% |
554,500
+166,100
| +43% | +$4.56M |
|
639
CALL
Ross Stores
ROST
$76.4B
| $15.5M | 0.01% |
86,000
+41,100
| +92% | +$6.86M |
|
640
CALL
Oneok
OKE
$57.8B
| $15.4M | 0.01% |
218,600
-17,900
| -8% | -$1.27M |
|
641
CALL
Grayscale Bitcoin Trust
GBTC
$9.91B
| $15.4M | 0.01% |
224,900
+121,800
| +118% | +$9.55M |
|
642
lululemon athletica
LULU
$12.9B
| $15.4M | 0.01% |
73,917
+49,485
| +203% | +$8.96M |
|
643
PUT
Twilio
TWLO
$27.8B
| $15.3M | 0.01% |
107,700
-11,800
| -10% | -$1.46M |
|
644
CALL
Upstart Holdings
UPST
$2.74B
| $15.3M | 0.01% |
349,800
-679,400
| -66% | -$31.3M |
|
645
CALL
TMC The Metals Company
TMC
$1.7B
| $15.3M | 0.01% |
2,479,100
+1,621,900
| +189% | +$11.4M |
|
646
PUT
Humana
HUM
$47.7B
| $15.3M | 0.01% |
59,600
-42,300
| -42% | -$11.1M |
|
647
Alphabet (Google) Class C
GOOG
$4.17T
| $15.2M | 0.01% |
48,506
+16,094
| +50% | +$4.61M |
|
648
PUT
Rio Tinto
RIO
$150B
| $15.2M | 0.01% |
190,100
-28,800
| -13% | -$2.07M |
|
649
PUT
Nucor
NUE
$53.7B
| $15.2M | 0.01% |
93,200
-36,900
| -28% | -$5.55M |
|
650
CALL
Southern Company
SO
$108B
| $15.2M | 0.01% |
174,200
-94,300
| -35% | -$8.61M |
|
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.