An employer that pays contributions to more than one state UI fund must file:

An employer that pays contributions to more than one state Unemployment Insurance (UI) fund is required to file Form 940. This form is specifically designed for reporting and paying federal unemployment taxes (FUTA). Employers who make contributions to multiple state UI programs can utilize Form 940 to report their federal obligations related to unemployment compensation.

Form 940 accounts for employer contributions, which include wages paid to employees subject to state UI tax. This is particularly relevant for employers who may be paying into multiple states due to having employees working in different jurisdictions or having a business presence that spans multiple states.

The other forms listed serve different purposes: Form 944 is an annual return that allows eligible small employers to report and pay their payroll taxes, Form 941 is a quarterly return for reporting income taxes withheld and social security and Medicare taxes, and Form 941c is used specifically for amending previously filed Form 941. None of these forms address the requirements for employers paying into multiple state UI funds as Form 940 does.