Similar to the more traditional money market funds (MMFs), stablecoins aim to provide investors with safe, money-like assets. We investigate similarities and differences between these two investment products. Our key finding is that, like MMFs, stablecoins also suffer from “flight-to-safety” dynamics. This is manifested in net flows from riskier to safer stablecoins on days of crypto-market stress. The same flight-to-safety dynamics also characterized flows during stablecoin runs, as exemplified by the two most severe episodes in 2022 and 2023. Furthermore, as flight-to-safety flows occur within MMF families, stablecoin flows tend to occur within blockchains.