Bill Gross isn’t buying the Trump rally and the prospects for growth driving it.

As President-elect Donald Trump’s economic team takes shape, led by Treasury Secretary nominee Steven Mnuchin, investors are misguided in betting that promised tax cuts, infrastructure spending and deregulation will spur faster growth, according to an e-mail Thursday from Gross, the billionaire bond fund manager. He said the benefits from such fiscal stimulus likely would be temporary.

Gross said future growth is primarily a function of productivity, which has flat lined for the last several years and shows little promise of accelerating.

“A strong dollar and continuing structural headwinds including aging demographics, de-globalization trade policies, and accelerating debt-to-GDP in almost all countries at now higher interest rates, promise to contain productivity at perhaps 1 percent annual growth rates and therefore real GDP growth at 2 percent,” he wrote.

The Dow Jones Industrial Average was up Thursday, the 13th daily gain in the 16 trading days since Trump’s surprise Nov. 8 election victory. Treasuries extended losses, continuing the biggest increase in yields on 10-year notes since 2009 following Trump’s triumph. Yields on the 10-year may rise to almost 2.5 percent by the end of this month, Gross said.

“An investor should move to cash and cash alternatives, such as high probability equity arbitrage situations,” Gross, who runs the $1.7 billion Janus Global Unconstrained Bond Fund, said. “Bond durations should be far below benchmarks.”

Jeffrey Gundlach, whose DoubleLine Capital oversaw more than $106 billion as of Sept. 30, also warned investors Thursday to be wary of a Trump rally.

“There is going to be a buyer’s remorse period," Gundlach said in an interview with Reuters. “The dollar is going to go down, yields have peaked and will move sideways, stocks have peaked as well and gold is going to go up in the short term.”