Veteran financial guru and former Ronald Reagan adviser Larry Kudlow said robust business investment has gone missing and is starving the economy of productivity.

As a result, the U.S. economy will continue to yield lackluster growth.

“There’s some spending going on. What’s missing is investment, business investment,” the Newsmax Finance Insider told CNBC.

“The single most important part of the economy in my judgment and, behind that what’s missing is productivity,” said Kudlow — host of “The Larry Kudlow Show” and author of “JFK and the Reagan Revolution: A Secret History of American Prosperity,” written with Brian Domitrovic and published by Portfolio.

He said corporate-tax reform is the key to resolving the situation.

“Repatriation, get the cash over here so it can be invested. Slash the business tax rates for large and small companies and immediate expensing so you’ll get your investment triggered right away,” said Kudlow, a radio talk-show host and CNBC