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 | |
|---|---|---|---|---|---|---|
2951
Burlington
BURL
$22.5B
| $715K | ﹤0.01% |
2,474
-4,350
| -64% | -$1.18M |
|
2952
FIVE9
FIVN
$1.96B
| $714K | ﹤0.01% |
35,629
+5,820
| +20% | +$124K |
|
2953
Dianthus Therapeutics
DNTH
$5.71B
| $714K | ﹤0.01% |
17,333
+11,020
| +175% | +$427K |
|
2954
PUT
Liberty Global Class C
LBTYK
$3.27B
| $712K | ﹤0.01% |
63,900
+7,500
| +13% | +$83.4K |
|
2955
CALL
American Resources Corp
AREC
$188M
| $712K | ﹤0.01% |
286,900
+177,300
| +162% | +$591K |
|
2956
CALL
Sinclair Inc
SBGI
$974M
| $711K | ﹤0.01% |
46,500
+43,800
| +1,622% | +$650K |
|
2957
PUT
Imperial Petroleum
IMPP
$217M
| $711K | ﹤0.01% |
196,400
+137,400
| +233% | +$676K |
|
2958
CALL
Build-A-Bear
BBW
$428M
| $711K | ﹤0.01% |
11,600
-10,900
| -48% | -$593K |
|
2959
CALL
Arvinas
ARVN
$530M
| $710K | ﹤0.01% |
59,900
-133,900
| -69% | -$1.46M |
|
|
OPRA
2960
Opera Ltd
OPRA
$1.69B
| $710K | ﹤0.01% |
+50,151
| New | +$740K |
|
2961
CALL
Butterfly Network
BFLY
$1.85B
| $710K | ﹤0.01% |
186,800
+72,400
| +63% | +$197K |
|
2962
CALL
Jones Lang LaSalle
JLL
$15.5B
| $707K | ﹤0.01% |
2,100
+1,600
| +320% | +$502K |
|
2963
Mobileye
MBLY
$2.02B
| $706K | ﹤0.01% |
67,612
-134,427
| -67% | -$1.68M |
|
2964
PUT
Transmedics
TMDX
$2.57B
| $706K | ﹤0.01% |
5,800
-41,300
| -88% | -$5.18M |
|
2965
CALL
Willdan Group
WLDN
$1.09B
| $705K | ﹤0.01% |
6,800
-3,100
| -31% | -$305K |
|
2966
CALL
M/I Homes
MHO
$3.81B
| $704K | ﹤0.01% |
5,500
+3,900
| +244% | +$516K |
|
2967
PUT
Carlyle Group
CG
$16.7B
| $703K | ﹤0.01% |
11,900
-27,700
| -70% | -$1.57M |
|
2968
Global E Online
GLBE
$6.34B
| $703K | ﹤0.01% |
17,889
-46,596
| -72% | -$1.73M |
|
2969
CALL
Noble Corp
NE
$6.88B
| $703K | ﹤0.01% |
24,900
-156,700
| -86% | -$4.63M |
|
2970
PUT
Powell Industries
POWL
$7.99B
| $701K | ﹤0.01% |
6,600
+3,000
| +83% | +$337K |
|
|
AWTM
2971
CALL
DELISTED
AWTM Ultra-Short Duration Enhanced Income ETF
AWTM
| $700K | ﹤0.01% |
28,300
+12,600
| +80% | +$312K |
|
2972
Rubrik
RBRK
$15.4B
| $700K | ﹤0.01% |
9,152
-36,276
| -80% | -$2.78M |
|
2973
Omnicom Group
OMC
$23.5B
| $700K | ﹤0.01% |
+8,667
| New | +$662K |
|
2974
CALL
MINISO
MNSO
$3.72B
| $699K | ﹤0.01% |
37,300
+24,800
| +198% | +$515K |
|
2975
PUT
Option Care Health
OPCH
$3.42B
| $698K | ﹤0.01% |
21,900
+7,400
| +51% | +$217K |
|
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.