Update says completed but yesterday's cost looks too low

There is a known reason and it is Google's rather than ours, but the practical advice is worth having. Google's own reporting isn't final the moment a day ends. Cost and click data for yesterday continues to firm up during the following day, and how long that takes varies by account size and by how much of your traffic came through partners. A completed update means we successfully retrieved everything Google was willing to give us at that moment - not that Google had finished counting. So an 8am reading of yesterday being light is normal, and by late morning it usually looks right. Two things that would make it worth investigating rather than waiting: The gap is still there tomorrow. Yesterday should be essentially settled within about a day, cost-wise. Conversions keep moving for much longer, cost doesn't. The pattern only affects some campaigns. A uniform shortfall across the account is a timing artefact. One campaign at zero while the others look normal is a different problem, usually access or a campaign that genuinely stopped. If it is still 40 percent short tomorrow afternoon, tell us the account and the date and we will compare what the API returned against what the interface shows.