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 | |
|---|---|---|---|---|---|---|
4801
Brown & Brown
BRO
$23.7B
| $120K | ﹤0.01% |
1,501
+1,198
| +395% | +$100K |
|
4802
CALL
Amer Sports
AS
$21B
| $120K | ﹤0.01% |
3,200
-67,100
| -95% | -$2.3M |
|
|
SGMO
4803
PUT
DELISTED
SANGAMO THERAPEUTICS INC
SGMO
| $119K | ﹤0.01% |
284,300
-57,700
| -17% | -$30.6K |
|
4804
GrafTech
EAF
$169M
| $119K | ﹤0.01% |
+7,697
| New | +$117K |
|
4805
Accel Entertainment
ACEL
$973M
| $119K | ﹤0.01% |
10,459
+8,729
| +505% | +$91.9K |
|
4806
PUT
Turning Point Brands
TPB
$1.47B
| $119K | ﹤0.01% |
1,100
-2,500
| -69% | -$244K |
|
|
BCIM
4807
CALL
DELISTED
abrdn Bloomberg Industrial Metals Strategy K-1 Free ETF
BCIM
| $119K | ﹤0.01% |
+6,100
| New | +$136K |
|
|
HIMX
4808
Himax Technologies
HIMX
$2.19B
| $119K | ﹤0.01% |
+14,542
| New | +$123K |
|
4809
LKQ Corp
LKQ
$5.76B
| $119K | ﹤0.01% |
+3,943
| New | +$119K |
|
4810
PUT
NovoCure
NVCR
$1.77B
| $119K | ﹤0.01% |
9,200
-26,800
| -74% | -$344K |
|
4811
PUT
Post Holdings
POST
$4.21B
| $119K | ﹤0.01% |
1,200
-2,800
| -70% | -$290K |
|
|
CRESY
4812
PUT
Cresud
CRESY
$823M
| $119K | ﹤0.01% |
9,400
-20,450
| -69% | -$226K |
|
|
AIRO
4813
CALL
AIRO Group Holdings
AIRO
$206M
| $119K | ﹤0.01% |
14,500
+9,200
| +174% | +$119K |
|
4814
PUT
Cogent Communications
CCOI
$663M
| $119K | ﹤0.01% |
5,500
-52,100
| -90% | -$1.54M |
|
|
BTOP
4815
DELISTED
Bitwise Bitcoin and Ether Equal Weight Strategy ETF
BTOP
| $119K | ﹤0.01% |
+4,120
| New | +$131K |
|
|
OPTU
4816
CALL
Optimum Communications Inc
OPTU
$290M
| $118K | ﹤0.01% |
71,800
-43,000
| -37% | -$87.5K |
|
4817
Clearwater Paper
CLW
$341M
| $118K | ﹤0.01% |
6,806
-963
| -12% | -$17.8K |
|
4818
PUT
Ardelyx
ARDX
$1.25B
| $118K | ﹤0.01% |
20,300
-6,600
| -25% | -$36.8K |
|
4819
PUT
Hafnia
HAFN
$3.84B
| $118K | ﹤0.01% |
22,200
+9,700
| +78% | +$57.8K |
|
4820
PUT
VistaGen Therapeutics
VTGN
$9.89M
| $118K | ﹤0.01% |
178,700
+131,200
| +276% | +$474K |
|
4821
Opko Health
OPK
$993M
| $118K | ﹤0.01% |
93,881
-56,685
| -38% | -$78.9K |
|
|
EB
4822
DELISTED
Eventbrite
EB
| $118K | ﹤0.01% |
+26,569
| New | +$82.3K |
|
4823
PUT
Park Hotels & Resorts
PK
$3.03B
| $118K | ﹤0.01% |
11,300
-9,000
| -44% | -$96.4K |
|
4824
PUT
Adecoagro
AGRO
$1.47B
| $118K | ﹤0.01% |
+14,900
| New | +$117K |
|
4825
CALL
Cavco Industries
CVCO
$4.33B
| $118K | ﹤0.01% |
+200
| New | +$113K |
|
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.