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 | |
|---|---|---|---|---|---|---|
4276
ProKidney
PROK
$316M
| $193K | ﹤0.01% |
86,046
+8,228
| +11% | +$21.6K |
|
|
DGXX
4277
Digi Power X Inc
DGXX
$325M
| $192K | ﹤0.01% |
+75,413
| New | +$283K |
|
4278
CALL
NETSCOUT
NTCT
$2.83B
| $192K | ﹤0.01% |
+7,100
| New | +$192K |
|
4279
PUT
Ascendis Pharma A/S
ASND
$16.5B
| $192K | ﹤0.01% |
900
-1,400
| -61% | -$289K |
|
|
CTLP
4280
DELISTED
Cantaloupe
CTLP
| $191K | ﹤0.01% |
18,028
+11,087
| +160% | +$118K |
|
4281
CALL
East-West Bancorp
EWBC
$17.8B
| $191K | ﹤0.01% |
1,700
-2,800
| -62% | -$297K |
|
|
TECX
4282
Tectonic Therapeutic
TECX
$536M
| $191K | ﹤0.01% |
9,142
+8,374
| +1,090% | +$156K |
|
4283
SandRidge Energy
SD
$503M
| $190K | ﹤0.01% |
+13,174
| New | +$174K |
|
4284
CALL
Extreme Networks
EXTR
$3.8B
| $190K | ﹤0.01% |
11,400
-2,200
| -16% | -$40.4K |
|
4285
PUT
Par Pacific Holdings
PARR
$4.17B
| $190K | ﹤0.01% |
5,400
-1,700
| -24% | -$67.6K |
|
4286
CALL
CrossAmerica Partners
CAPL
$834M
| $190K | ﹤0.01% |
9,200
+1,000
| +12% | +$20.6K |
|
4287
CALL
Prenetics Global
PRE
$306M
| $189K | ﹤0.01% |
+12,000
| New | +$175K |
|
4288
CALL
Zimmer Biomet
ZBH
$18.8B
| $189K | ﹤0.01% |
2,100
-11,800
| -85% | -$1.12M |
|
|
UPSX
4289
Tradr 2X Long UPST Daily ETF
UPSX
$17.8M
| $189K | ﹤0.01% |
+3,812
| New | +$229K |
|
|
SNBR
4290
CALL
DELISTED
Sleep Number
SNBR
| $189K | ﹤0.01% |
22,300
+3,000
| +16% | +$19K |
|
4291
Evolent Health
EVH
$371M
| $189K | ﹤0.01% |
47,159
+41,742
| +771% | +$232K |
|
4292
CALL
Associated Banc-Corp
ASB
$5.8B
| $188K | ﹤0.01% |
7,300
-1,500
| -17% | -$38.6K |
|
4293
PUT
Kyverna Therapeutics
KYTX
$430M
| $188K | ﹤0.01% |
+20,000
| New | +$148K |
|
4294
Spire Global
SPIR
$408M
| $188K | ﹤0.01% |
+25,045
| New | +$245K |
|
4295
CALL
Fortive
FTV
$18.2B
| $188K | ﹤0.01% |
3,400
-56,800
| -94% | -$2.95M |
|
4296
PUT
Pentair
PNR
$10.8B
| $187K | ﹤0.01% |
1,800
+1,300
| +260% | +$139K |
|
|
MOMO
4297
PUT
Hello Group
MOMO
$867M
| $187K | ﹤0.01% |
28,600
-66,800
| -70% | -$460K |
|
4298
CALL
Gulfport Energy Corp
GPOR
$2.82B
| $187K | ﹤0.01% |
900
-1,300
| -59% | -$259K |
|
4299
CALL
Commercial Metals
CMC
$7.53B
| $187K | ﹤0.01% |
2,700
-12,000
| -82% | -$751K |
|
4300
CALL
Philips
PHG
$25.5B
| $187K | ﹤0.01% |
7,156
-11,927
| -63% | -$318K |
|
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.