A lawmaker skeptical of the Big Ten’s proposed $2.4 billion deal with a private investor has requested a Congressional analysis of the tax consequences for the NCAA, its schools and conferences in the changing college sports industry. “Legitimate questions have been raised about whether it is time to rethink the tax-exempt regime under which college sports currently operates,” Sen. Maria Cantwell, D-Wash., wrote in a letter Monday to the head of the Congressional Joint Committee on Taxation.