The stock market is serving as the Trump administration's economic report card, in the view of Steven Mnuchin, but the new Treasury secretary may have just named a risky way to define success.

Anyone wondering whether the business community is behind President Donald Trump only needs to look at financial markets for answers. Markets have been on a tear since the Republican won election in November. The has jumped more than 10 percent since, and the stock market in general has been off to one of the fastest starts ever for a new president.

For Mnuchin, that is a signal of optimism that the new administration will deliver on its promises for a booming economy.

"There's a lot of confidence in the Trump administration and in the desire to invest in the U.S.," he told CNBC in an exclusive interview Thursday. "This is a very competitive place to do business. We've got great companies, and you see that reflected in the markets."

During his first month in office, Trump has pushed an agenda that includes broad-based tax cuts, a reduction in regulations and a focus on government spending to upgrade the nation's aging infrastructure.

The markets have responded in kind, with the major averages getting a boost and a rush of investor money coming off the sidelines. Funds focused on U.S. stocks have taken in $52.3 billion in 2017 alone.