Final answer:
Based on the cumulative liability for FUTA tax, Leonard's first FUTA deposit was due by October 31st, following the third quarter's end.
Step-by-step explanation:
Leonard's first FUTA deposit was due on the last day of the month following the end of the quarter in which his Federal Unemployment (FUTA) tax liability was over $500. Since the FUTA tax liability for the first quarter was $235, under the $500 threshold, no deposit was necessary.
However, adding the second quarter's liability of $190, the cumulative amount was $425, still under the $500 threshold. It was not until the third quarter, with an additional liability of $150, that Leonard's cumulative FUTA tax liability exceeded $500, reaching $575.
Therefore, Leonard's first FUTA deposit was due by October 31st, which is the last day of the month following the third quarter that ended on September 30th.