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 | |
|---|---|---|---|---|---|---|
5326
First Trust NASDAQ Cybersecurity ETF
CIBR
$14.4B
| $71K | ﹤0.01% |
994
-6,651
| -87% | -$498K |
|
5327
CALL
Trupanion
TRUP
$1.07B
| $71K | ﹤0.01% |
1,900
-1,700
| -47% | -$66.8K |
|
5328
CALL
Vishay Intertechnology
VSH
$5.25B
| $71K | ﹤0.01% |
4,900
-9,500
| -66% | -$144K |
|
5329
CALL
Neurocrine Biosciences
NBIX
$16.8B
| $70.9K | ﹤0.01% |
500
-4,000
| -89% | -$579K |
|
|
FIAT
5330
YieldMax Short COIN Option Income Strategy ETF
FIAT
$36.8M
| $70.8K | ﹤0.01% |
+2,533
| New | +$65.9K |
|
5331
PUT
Graham Corp
GHM
$1.12B
| $70.7K | ﹤0.01% |
1,100
-200
| -15% | -$12.1K |
|
5332
PUT
SiTime
SITM
$16B
| $70.6K | ﹤0.01% |
200
-500
| -71% | -$156K |
|
5333
Palladyne AI
PDYN
$247M
| $70.6K | ﹤0.01% |
16,569
-85,594
| -84% | -$576K |
|
5334
PUT
First Trust Consumer Discretionary AlphaDEX Fund
FXD
$269M
| $70.6K | ﹤0.01% |
600
-31,000
| -98% | -$2.08M |
|
|
NSA
5335
CALL
DELISTED
National Storage Affiliates Trust
NSA
| $70.5K | ﹤0.01% |
2,500
+1,100
| +79% | +$32.8K |
|
5336
CALL
Renasant Corp
RNST
$3.98B
| $70.4K | ﹤0.01% |
2,000
-31,500
| -94% | -$1.12M |
|
|
ALMU
5337
CALL
Aeluma Inc
ALMU
$297M
| $70.4K | ﹤0.01% |
4,100
+3,800
| +1,267% | +$60K |
|
5338
PUT
SES AI
SES
$203M
| $70.4K | ﹤0.01% |
39,100
-107,700
| -73% | -$241K |
|
5339
CALL
Ziff Davis
ZD
$1.96B
| $70.3K | ﹤0.01% |
2,000
+1,900
| +1,900% | +$66.2K |
|
|
5340
PUT
Ziff Davis
ZD
$1.96B
| $70.3K | ﹤0.01% |
2,000
-28,500
| -93% | -$994K |
|
5341
CALL
Archrock
AROC
$6.27B
| $70.3K | ﹤0.01% |
2,700
-1,500
| -36% | -$37.3K |
|
5342
Medtronic
MDT
$109B
| $70.2K | ﹤0.01% |
+731
| New | +$71K |
|
|
BCAX
5343
Bicara Therapeutics
BCAX
$1.78B
| $70.1K | ﹤0.01% |
4,167
+3,159
| +313% | +$54K |
|
5344
GeoPark
GPRK
$633M
| $70K | ﹤0.01% |
9,440
-21,615
| -70% | -$158K |
|
5345
PUT
Neogen
NEOG
$2.63B
| $69.9K | ﹤0.01% |
10,000
-101,700
| -91% | -$640K |
|
5346
Insperity
NSP
$1.93B
| $69.9K | ﹤0.01% |
+1,805
| New | +$72.1K |
|
5347
CALL
STAG Industrial
STAG
$7.38B
| $69.8K | ﹤0.01% |
1,900
-8,800
| -82% | -$334K |
|
5348
CALL
Telesat
TSAT
$567M
| $69.8K | ﹤0.01% |
2,400
-10,300
| -81% | -$299K |
|
|
CIVI
5349
DELISTED
Civitas Resources
CIVI
| $69.8K | ﹤0.01% |
2,578
-6,107
| -70% | -$177K |
|
5350
CALL
Gaotu Techedu
GOTU
$434M
| $69.8K | ﹤0.01% |
30,100
-1,600
| -5% | -$4.34K |
|
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.