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 | |
|---|---|---|---|---|---|---|
3676
PUT
Flowserve
FLS
$9.38B
| $347K | ﹤0.01% |
+5,000
| New | +$321K |
|
3677
PUT
AllianceBernstein
AB
$3.49B
| $346K | ﹤0.01% |
9,000
-4,900
| -35% | -$194K |
|
|
SAIL
3678
CALL
SailPoint Inc
SAIL
$8.95B
| $346K | ﹤0.01% |
17,100
-31,800
| -65% | -$663K |
|
3679
PUT
Global Net Lease
GNL
$1.86B
| $346K | ﹤0.01% |
40,200
-13,900
| -26% | -$111K |
|
|
BULL
3680
Webull Corp
BULL
$3.87B
| $346K | ﹤0.01% |
+44,482
| New | +$447K |
|
3681
PUT
Senseonics Holdings Inc
SENS
$256M
| $346K | ﹤0.01% |
62,600
+53,565
| +593% | +$373K |
|
3682
PUT
Green Brick Partners
GRBK
$3.18B
| $345K | ﹤0.01% |
5,500
+2,300
| +72% | +$152K |
|
3683
Equifax
EFX
$22B
| $344K | ﹤0.01% |
+1,587
| New | +$348K |
|
3684
PUT
Itron
ITRI
$4.75B
| $344K | ﹤0.01% |
+3,700
| New | +$403K |
|
3685
CALL
Atlas Lithium Corp
ATLX
$79.3M
| $343K | ﹤0.01% |
81,200
+26,900
| +50% | +$136K |
|
|
GOOS
3686
CALL
Canada Goose Holdings
GOOS
$903M
| $343K | ﹤0.01% |
26,500
-36,400
| -58% | -$484K |
|
3687
Howard Hughes
HHH
$4B
| $343K | ﹤0.01% |
4,298
+1,042
| +32% | +$86.3K |
|
|
FLNA
3688
Filana Therapeutics
FLNA
$42.7M
| $343K | ﹤0.01% |
173,065
+11,387
| +7% | +$36.5K |
|
3689
CALL
Voya Financial
VOYA
$9.07B
| $343K | ﹤0.01% |
4,600
-15,000
| -77% | -$1.09M |
|
3690
PUT
Smith & Wesson
SWBI
$657M
| $342K | ﹤0.01% |
34,700
-52,900
| -60% | -$511K |
|
3691
CALL
Corteva
CTVA
$59.5B
| $342K | ﹤0.01% |
5,100
-35,900
| -88% | -$2.32M |
|
3692
Solid Biosciences
SLDB
$785M
| $341K | ﹤0.01% |
60,534
-23,467
| -28% | -$127K |
|
3693
PUT
ArcBest
ARCB
$3.33B
| $341K | ﹤0.01% |
4,600
+3,600
| +360% | +$256K |
|
3694
CMS Energy
CMS
$23B
| $341K | ﹤0.01% |
4,876
+4,291
| +734% | +$312K |
|
3695
CALL
Amylyx Pharmaceuticals
AMLX
$2.17B
| $341K | ﹤0.01% |
28,200
-43,300
| -61% | -$588K |
|
3696
CALL
Clearway Energy Class C
CWEN
$4.9B
| $340K | ﹤0.01% |
10,400
-4,500
| -30% | -$150K |
|
3697
PUT
Lightbridge
LTBR
$259M
| $340K | ﹤0.01% |
26,900
-61,700
| -70% | -$1.19M |
|
3698
PUT
Commercial Metals
CMC
$7.8B
| $339K | ﹤0.01% |
4,900
-38,200
| -89% | -$2.39M |
|
3699
PUT
ProKidney
PROK
$316M
| $339K | ﹤0.01% |
151,400
-26,600
| -15% | -$70K |
|
3700
CALL
Achieve Life Sciences
ACHV
$634M
| $339K | ﹤0.01% |
68,200
-189,700
| -74% | -$827K |
|
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.