In 2017, there were about 100 digital challenger banks around the globe.
They held nearly $161 billion in total global banking assets.
By 2020, challengers' total global banking assets quadrupled as the number of digital banks increased more than twofold.
Today, there are about 250 challenger banks. However, most technically aren't banks since they don't have a banking license.
Moody's analysis focuses on the 20 challenger banks that hold a banking license.
The 20 licensed virtual banks are among the largest, holding nearly half of all challenger banks' assets in 2020.
Japan's Rakuten Bank, the largest licensed challenger, held $58.7 billion.
Click or tap banks to show historic assets growth
Digital banks, however, are still minnows compared with traditional banks. Challengers — licensed and unlicensed combined — hold only 0.4% of the world's banking assets.
While the 20 licensed challengers in our analysis represent an even smaller share.