We report the observation of a coalescing compact binary with component masses 2.5？4.5 M e and 1.2？2.0 M e (all measurements quoted at the 90% credible level). The gravitational-wave signal GW230529_181500 was observed during the fourth observing run of the LIGO？Virgo？KAGRA detector network on 2023 May 29 by the LIGO Livingston observatory.
