(Bloomberg) — Alan Greenspan is worried bond prices have risen too high.

(Bloomberg News)
“We’re just in a stagnation state,” Alan Greenspan says.

“We get very nervous when the stock price index goes to high P/E, we ought to be somewhat nervous when the bond rate does the same,” the former Fed chairman said in an interview Thursday with Bloomberg Television.
Some bond market metrics show prices are getting frothy, after yields on 10-year Treasurys sank to a record 1.32% this month.

The maturity now yields less than stocks pay in dividends. And a measure known as the term premium, which has historically been positive, fell to an unprecedented minus 0.75% this month for 10-year Treasurys. The metric, which the Fed uses in guiding policy, reflects the extra compensation investors demand to hold longer-maturity debt instead of successive short-term securities.

Read more:

Treasuries have rallied in 2016 as the Fed held off on raising interest rates after liftoff from near zero in December, while central banks in Japan and Europe maintained unprecedented stimulus. Policy makers on Wednesday left the federal funds rate at 0.25% to 0.5% while saying near-term risks to the economic outlook were dissipating, keeping the option to raise rates in September open.

Benchmark U.S. 10-year note yields rose three basis points, or 0.03%, to 1.53% as of 9:10 a.m. in New York, according to Bloomberg Bond Trader data.

Corporate supply, including offerings from Apple, also weakened investors’ appetite for Treasurys.

PRESSURE ON

"We had a big rally after the Fed, even though the Fed sounded hawkish," said Aaron Kohli, a fixed-income strategist in New York at BMO Capital Markets, one of the 23 primary dealers that trade with Fed. "More importantly, there’s expectations of corporate supply today, which is keeping pressure on yields."

Treasurys also declined as investors prepared for the final leg of the week’s $103 billion of coupon-bearing government-debt auctions. The U.S. is selling $28 billion of seven-year notes Thursday, after previous offerings this week drew weak demand.

Read more:

Greenspan also said the U.S. may be heading toward stagflation -- a slow-growth economy coupled with high inflation. That condition isn’t compatible with long-term interest rates of 1% to 2%. There’s a significant amount of uncertainty and “general sluggishness" in the economy, which is tied to low productivity, he said.

“What I’m concerned about mostly is stagflation, meaning I think we’re seeing the very early signs of inflation beginning finally to pick up as the issue of deflation fades,” Greenspan, 90, said. “We’re just in a stagnation state.”