We study intraday liquidity usage and its determinants using a unique cross-country data set on large-value payments. We document that the amount of intraday liquidity that nancial institutions around the world use each day equals, on average, 15% of their total daily payment values or 2.8% of their countries' GDP. We then dene and calculate system-level measures of liquidity eciency and inequality in liquidity provision. We show that these measures vary systematically with the degree of payment coordination among payment system participants, the quantity and opportunity cost of central bank reserves and institutional characteristics, such as incentives for early payment submission and liquidity saving mechanism (LSM) design. Our results are consistent with the notion that payment system participants behave strategically and manage intraday liquidity actively. Participants also appear to condition their payment behaviour on specic LSM characteristics, which may weaken some of the LSMs' intended eects.