These are stable cryptoassets whose value is pegged to the US dollar in a proportion of 1 to 1, thus also called digital dollars. If you’d like to know more about USD stablecoins, have a look at the following article: How do stablecoins work at Bitso?
When holding USD stablecoins at Bitso, your funds will be composed of the USD basket, a combination of USD Coin (USDC) and Pax Dollar (USDP). These three are cryptoassets with proof of reserve in cash or dollar related assets, which brings more stability and security to the stablecoins under our custody.