> For the complete documentation index, see [llms.txt](https://docs.avantisfi.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.avantisfi.com/trading/collateral.md). # Collateral ### USDC Traders put up USDC (Circle's digital US dollar) as their collateral for trades, and LPs invest USDC into our market-making vaults. We use Circle's USDC as our stablecoin of choice, as it is one of the world's largest stablecoins with a proven and safe track record, and a stablecoin that is available on several exchanges around the world (while being readily available on both Optimism and Base). It is very easy for a trader to swap out their stablecoin into USDC within our app. We did not want to create our own stablecoin, use a less capital efficient stablecoin like DAI, or use a partially regulated stablecoin like Tether. Learn more about USDC from Circle, the company that creates USDC.