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 | |
|---|---|---|---|---|---|---|
3226
Vanguard Tax-Exempt Bond Index Fund
VTEB
$45.2B
| $543K | ﹤0.01% |
10,806
+9,460
| +703% | +$476K |
|
3227
PUT
ARK 21Shares Bitcoin ETF
ARKB
$2.47B
| $543K | ﹤0.01% |
18,700
-83,900
| -82% | -$2.79M |
|
3228
CALL
First Trust Exchange-Traded Fund VI Multi-Asset Diversified Income Index Fund
MDIV
$428M
| $543K | ﹤0.01% |
5,600
-200
| -3% | -$3.16K |
|
|
AISP
3229
CALL
Airship AI Holdings
AISP
$67.8M
| $542K | ﹤0.01% |
187,700
-100,900
| -35% | -$416K |
|
3230
GSI Technology
GSIT
$222M
| $542K | ﹤0.01% |
87,314
+24,975
| +40% | +$178K |
|
3231
CALL
HealthEquity
HQY
$8.28B
| $540K | ﹤0.01% |
5,900
-8,600
| -59% | -$823K |
|
3232
PUT
Ecopetrol
EC
$32.5B
| $540K | ﹤0.01% |
53,900
-28,500
| -35% | -$272K |
|
|
CAN
3233
CALL
Canaan Creative
CAN
$192M
| $540K | ﹤0.01% |
782,600
+343,700
| +78% | +$394K |
|
3234
Syndax Pharmaceuticals
SNDX
$1.82B
| $539K | ﹤0.01% |
+25,660
| New | +$448K |
|
3235
PUT
Kaspi.kz JSC
KSPI
$16.4B
| $539K | ﹤0.01% |
6,900
-100
| -1% | -$7.56K |
|
3236
CALL
First Trust Consumer Discretionary AlphaDEX Fund
FXD
$269M
| $539K | ﹤0.01% |
4,800
-5,400
| -53% | -$362K |
|
3237
RadNet
RDNT
$4.84B
| $539K | ﹤0.01% |
+7,549
| New | +$583K |
|
|
PCH
3238
PUT
DELISTED
PotlatchDeltic
PCH
| $537K | ﹤0.01% |
13,500
+7,600
| +129% | +$308K |
|
3239
Delek US
DK
$3.95B
| $536K | ﹤0.01% |
18,080
+8,532
| +89% | +$305K |
|
3240
Phillips 66
PSX
$83.3B
| $536K | ﹤0.01% |
4,155
-18,927
| -82% | -$2.55M |
|
3241
PUT
Targa Resources
TRGP
$57.4B
| $535K | ﹤0.01% |
2,900
+400
| +16% | +$67.4K |
|
|
OS
3242
DELISTED
OneStream Inc
OS
| $534K | ﹤0.01% |
29,058
-9,532
| -25% | -$182K |
|
|
BLDP
3243
CALL
Ballard Power Systems
BLDP
$865M
| $534K | ﹤0.01% |
210,200
+123,400
| +142% | +$383K |
|
|
PBT
3244
PUT
Permian Basin Royalty Trust
PBT
$1.29B
| $533K | ﹤0.01% |
31,400
-14,400
| -31% | -$258K |
|
3245
CALL
BGC Group
BGC
$5.65B
| $533K | ﹤0.01% |
59,700
+58,500
| +4,875% | +$527K |
|
3246
Flutter Entertainment
FLUT
$18.4B
| $533K | ﹤0.01% |
+2,479
| New | +$558K |
|
|
AWTM
3247
PUT
DELISTED
AWTM Ultra-Short Duration Enhanced Income ETF
AWTM
| $532K | ﹤0.01% |
21,500
+14,000
| +187% | +$347K |
|
3248
Teradyne
TER
$52.4B
| $532K | ﹤0.01% |
+2,748
| New | +$471K |
|
3249
CALL
Marqeta
MQ
$1.85B
| $532K | ﹤0.01% |
27,975
-1,900
| -6% | -$36.5K |
|
3250
Global X Artificial Intelligence & Technology ETF
AIQ
$9.26B
| $531K | ﹤0.01% |
+10,450
| New | +$531K |
|
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.