Q. I'm an accountant so this is my busy time of the year in this country. I always tried to avoid working on Purim. Can I work during the night after the reading of the megillah?
A. Biur Halocho (696: 1) quotes P'ri Megodim saying that the proscription of working on Purim applies only during the day and not at night. However, Yeshuos Yaakov (690: 6) and Chassam Sofer (195) maintain that the night is included in the ban.
Horav Shlomo Miller's Shlit'a opinion is to be lenient in need. (See similar opinion from Horav Shmuel Kamenetzki Shlit'a in Kovetz Halochos 6: 4).
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit'a