Which tax form must employers file to report employment taxes?

Employers are required to file Form 941 to report employment taxes, specifically federal income tax withheld and both the employer's and employee's share of Social Security and Medicare taxes. This form is typically submitted quarterly and provides a comprehensive view of payroll taxes, allowing the IRS to monitor compliance and ensure that the correct amounts are being withheld from employees’ wages.

Form 940, on the other hand, is used to report annual Federal Unemployment Tax Act (FUTA) taxes. While Form W-2 is used to report wages and taxes withheld for individual employees at the end of the year, it does not serve the purpose of reporting employment taxes directly to the IRS. Form 1099 is primarily used to report various types of income other than wages, salaries, and tips, such as independent contractor payments, and is not relevant for employment tax reporting. Thus, Form 941 is the correct choice for reporting employment taxes in the context given.