The chairmen of the tax-writing committees -- whether they act together or alone -- don't need to disclose that they've requested the president's returns. But they may choose to -- and likely would -- share the returns with their committee members in closed session. If the committee thinks releasing the returns to the House or Senate would further a legitimate committee purpose, they're permitted to do so, according to George Yin, a former chief of staff at the Joint Committee on Taxation and a UVA professor of law.