Businesses that withhold wages from their employees are required to file 941-Employers Quarterly Federal Tax Return. These are filed each calendar quarter i.e. January thru March, filed April 30; April thru June, filed July 31; July thru September, filed October 31; and October thru December, filed January 31. Any business that pays more than $2500 in net taxes is required to make quarterly deposits to authorized financial institutions. Again, IRS is trying to aid businesses in being compliant with paying their tax.