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 | |
|---|---|---|---|---|---|---|
4676
Delcath Systems
DCTH
$400M
| $134K | ﹤0.01% |
13,283
-6,746
| -34% | -$67.1K |
|
4677
Carter's
CRI
$1.43B
| $134K | ﹤0.01% |
+4,135
| New | +$129K |
|
4678
CALL
Graphic Packaging
GPK
$3.35B
| $134K | ﹤0.01% |
8,900
-36,700
| -80% | -$603K |
|
4679
Global X Blockchain & Bitcoin Strategy ETF
BITS
$22.2M
| $134K | ﹤0.01% |
2,136
+2,130
| +35,500% | +$198K |
|
|
DFDV
4680
CALL
DeFi Development Corp
DFDV
$77.4M
| $134K | ﹤0.01% |
118,800
-184,800
| -61% | -$1.69M |
|
4681
PUT
Playtika
PLTK
$1.53B
| $134K | ﹤0.01% |
33,800
+100
| +0.3% | +$391 |
|
4682
PUT
Terex
TEX
$7.37B
| $133K | ﹤0.01% |
2,500
-31,700
| -93% | -$1.6M |
|
4683
CALL
Taysha Gene Therapies
TSHA
$1.61B
| $133K | ﹤0.01% |
24,200
+13,700
| +130% | +$66.5K |
|
4684
Olema Pharmaceuticals
OLMA
$977M
| $133K | ﹤0.01% |
5,321
-20,371
| -79% | -$362K |
|
4685
PUT
TransDigm Group
TDG
$70.7B
| $133K | ﹤0.01% |
100
-2,300
| -96% | -$3.01M |
|
4686
FreightCar America
RAIL
$263M
| $133K | ﹤0.01% |
11,997
+9,182
| +326% | +$84.4K |
|
4687
CALL
Duos Technologies
DUOT
$235M
| $133K | ﹤0.01% |
+11,800
| New | +$111K |
|
4688
Axalta
AXTA
$7.45B
| $133K | ﹤0.01% |
4,108
+3,554
| +642% | +$104K |
|
4689
PUT
Unusual Machines
UMAC
$825M
| $132K | ﹤0.01% |
10,400
-226,400
| -96% | -$2.66M |
|
|
CVGW
4690
DELISTED
Calavo Growers
CVGW
| $132K | ﹤0.01% |
6,078
+5,471
| +901% | +$121K |
|
4691
PUT
Glacier Bancorp
GBCI
$6.36B
| $132K | ﹤0.01% |
3,000
| – | – |
|
4692
WidePoint Corp
WYY
$97.4M
| $132K | ﹤0.01% |
24,585
+15,609
| +174% | +$97.1K |
|
4693
PUT
Kite Realty
KRG
$5.86B
| $132K | ﹤0.01% |
5,500
+4,400
| +400% | +$99.9K |
|
4694
CALL
Cardlytics
CDLX
$22.2M
| $131K | ﹤0.01% |
11,430
-10,200
| -47% | -$158K |
|
|
ZENA
4695
CALL
ZenaTech Inc
ZENA
$110M
| $131K | ﹤0.01% |
41,000
-1,900
| -4% | -$7.92K |
|
4696
PUT
Essex Property Trust
ESS
$19.1B
| $131K | ﹤0.01% |
500
+100
| +25% | +$25.9K |
|
|
TSMU
4697
GraniteShares 2x Long TSM Daily ETF
TSMU
$52.5M
| $131K | ﹤0.01% |
2,982
+1,902
| +176% | +$80K |
|
4698
Goldman Sachs BDC
GSBD
$997M
| $131K | ﹤0.01% |
+14,064
| New | +$138K |
|
4699
PUT
Lightspeed Commerce
LSPD
$1.44B
| $130K | ﹤0.01% |
10,800
-23,200
| -68% | -$275K |
|
4700
CEVA Inc
CEVA
$831M
| $130K | ﹤0.01% |
+6,061
| New | +$149K |
|
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.