Portable Benefits for Independent Workers Pilot Program Act This bill requires the Department of Labor to award grants for FY2018, on a competitive basis, to states, local governments, or nonprofit organizations to support broad innovation and experimentation with respect to portable benefits. Portable benefits are work-related benefits that are provided to eligible workers for eligible work in a manner that allows the worker to maintain the benefits upon changing jobs. The grants must be used for: (1) the evaluation, or improvement to the design or implementation, of existing models or approaches for providing portable benefits; or (2) the design, implementation, and evaluation of new models or approaches for providing such benefits. The grants may not be used for a model or approach that provides only retirement-related benefits. The Government Accountability Office must evaluate and report to Congress on the outcome of the grants awarded pursuant to this bill.