Former Clinton Treasury Secretary Larry Summers told CNBC Friday the U.S. economy is not growing fast enough.
While American economic growth is getting better and leads the rest of the world, investments need to be made to get the economy stronger, Summers said. "Confidence is the cheapest form of stimulus," he said on "Squawk Box."
"We're not doing well enough. We haven't had a year of 3 percent [growth] in a very long time in the United States," he said.
Summers, also a former Obama administration economic advisor, said the U.S. bond market is indicating that investors are worried. "With forward interest rates coming down as much as they have, it suggests concern about underlying growth in this economy."