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 | |
|---|---|---|---|---|---|---|
6276
CALL
PRA Group
PRAA
$663M
| $24.8K | ﹤0.01% |
1,400
-600
| -30% | -$9.34K |
|
|
WBTN
6277
PUT
WEBTOON Entertainment Inc
WBTN
$1.23B
| $24.8K | ﹤0.01% |
1,900
-135,900
| -99% | -$2.08M |
|
6278
CALL
BRC Inc
BRCC
$121M
| $24.8K | ﹤0.01% |
22,300
+21,200
| +1,927% | +$27.5K |
|
|
MITT
6279
CALL
TPG Mortgage Investment Trust
MITT
$222M
| $24.7K | ﹤0.01% |
2,900
-6,600
| -69% | -$51.8K |
|
6280
InflaRx
IFRX
$250M
| $24.7K | ﹤0.01% |
24,410
-59,047
| -71% | -$73.3K |
|
6281
CALL
Krystal Biotech
KRYS
$10.1B
| $24.7K | ﹤0.01% |
100
-200
| -67% | -$42.1K |
|
6282
Amplify Seymour Cannabis ETF
CNBS
$70.6M
| $24.7K | ﹤0.01% |
869
+777
| +845% | +$21.1K |
|
6283
Real Brokerage
REAX
$349M
| $24.7K | ﹤0.01% |
6,754
-151,341
| -96% | -$585K |
|
6284
CALL
Gencor Industries
GENC
$209M
| $24.6K | ﹤0.01% |
1,900
-8,300
| -81% | -$111K |
|
|
IMMP
6285
PUT
Immutep
IMMP
$56.3M
| $24.6K | ﹤0.01% |
+8,600
| New | +$18.1K |
|
6286
VanEck ChiNext Innovators ETF
CNXT
$105M
| $24.6K | ﹤0.01% |
561
-192
| -25% | -$8.18K |
|
6287
Cerus
CERS
$433M
| $24.5K | ﹤0.01% |
11,897
-31,351
| -72% | -$54.3K |
|
6288
Lantheus
LNTH
$6.49B
| $24.5K | ﹤0.01% |
+368
| New | +$21.4K |
|
|
FWDI
6289
PUT
Forward Industries Inc
FWDI
$297M
| $24.5K | ﹤0.01% |
3,700
-8,600
| -70% | -$110K |
|
6290
CALL
Artisan Partners
APAM
$2.79B
| $24.4K | ﹤0.01% |
600
-100
| -14% | -$4.27K |
|
6291
PUT
West Fraser Timber
WFG
$5.08B
| $24.4K | ﹤0.01% |
400
| – | – |
|
6292
CALL
Insight Enterprises
NSIT
$3.89B
| $24.4K | ﹤0.01% |
300
+100
| +50% | +$9.38K |
|
|
BELFB
6293
Bel Fuse Inc Class B
BELFB
$3.87B
| $24.4K | ﹤0.01% |
144
+139
| +2,780% | +$21.7K |
|
6294
Sana Biotechnology
SANA
$871M
| $24.4K | ﹤0.01% |
5,996
-66,427
| -92% | -$297K |
|
|
CEPU
6295
Central Puerto
CEPU
$2.29B
| $24.4K | ﹤0.01% |
1,393
+100
| +8% | +$1.38K |
|
6296
PUT
Koppers
KOP
$943M
| $24.4K | ﹤0.01% |
900
-4,700
| -84% | -$131K |
|
6297
CALL
Freedom Holding
FRHC
$9.63B
| $24.3K | ﹤0.01% |
200
-900
| -82% | -$131K |
|
6298
National Beverage
FIZZ
$2.96B
| $24.3K | ﹤0.01% |
763
+652
| +587% | +$22.4K |
|
|
DEFT
6299
PUT
Defi Technologies
DEFT
$156M
| $24.3K | ﹤0.01% |
32,200
-105,700
| -77% | -$162K |
|
|
SLN
6300
Silence Therapeutics
SLN
$495M
| $24.3K | ﹤0.01% |
3,991
+3,340
| +513% | +$21.4K |
|
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.