Sen. Charles Grassley, the ranking member of the Senate Finance Committee, sent lengthy questionnaires a month ago to six ministries so he could review whether pastors were complying with IRS rules that bar excessive personal gain through tax-exempt work.
However, two of those televangelists ignored Thursday's deadline to turn over information.
Benny Hinn of World Healing Center Church Inc. and Benny Hinn Ministries of Grapevine, Texas, said in a statement to the AP on Thursday that he will not respond to the inquiry until next year.
A lawyer for preacher Creflo Dollar of World Changers Church International in suburban Atlanta had said Wednesday that the investigation should be referred to the IRS or the Senate panel should get a subpoena for the documents.
All the ministries preach a form of "Word of Faith" theology, known as prosperity gospel, which teaches that God wants believers to reap material rewards for their faith.
Because they have tax status as churches, the ministries do not have to file IRS 990 forms like other non-profit organizations - leaving much financial information largely behind closed doors.
The letters sent Monday were the culmination of a long investigation fueled in part by complaints from Ole Anthony, a crusader against religious fraud who operates the Dallas-based Trinity Foundation, which describes itself as a watchdog monitoring religious media, fraud and abuse. "We've been working with them for two years," Anthony told CBS News. "We have furnished them with enough information to fill a small Volkswagen."
The other ministries targeted in the inquiry are Bishop Eddie Long of New Birth Missionary Baptist Church and Bishop Eddie Long Ministries of Lithonia, Ga.; Randy and Paula White of Without Walls International Church and Paula White Ministries of Tampa, Fla.; and Kenneth and Gloria Copeland of Kenneth Copeland Ministries of Newark, Texas.