Mnuchin said Sunday: "I have never heard Steve mention that."
Speaking on ABC News' "This Week," Mnuchin said the administration aims to release its full tax plan by September and to pass it into law by the end of the year. So far, the administration has issued a one-page summary of broad principles for tax reform, but few details.
The administration says it wants to reduce the top income tax bracket from 39.6% to 35% and lower tax rates for the middle class.
Jonathan Swan of the news website Axios reported last Sunday that chief strategist Steve Bannon wanted to get the top tax bracket, which stands at 39.5%, into the 40s. The top bracket applies to individuals making $418,400 or higher and couples making $470,700 or higher.
While this may not please many large Republican donors or political action groups, it is a popular message for tax reform. According to a Morning Consult/Politico poll in May, 62% of Americans believe that "upper-income people" pay too little in taxes.