Alan Greenspan believes the economy would thrive if America let more immigrants into the country.
The former Federal Reserve chair says the highly skilled migrant program -- the H-1B visa that is popular with tech companies -- should be a lot bigger.
"The H-1B visa program is much too small," Greenspan said Thursday at the Council on Foreign Relations in New York. "If we really wanted to increase productivity, we would really open that program up."
This year a record 233,000 foreigners applied for only 85,000 H-1B visas.
He believes anyone who gets a PhD in the sciences in the United States should be allowed to stay.
Greenspan was speaking a day after the Fed raised interest rates for the first time in nearly a decade.
He wouldn't say much about the Fed's move, but he did praise current Fed chair Janet Yellen and the committee for sending clear signals. He said the Fed prepared the markets well for the move and it reassured investors there would not be a series of rapid rate hikes.