Janet Yellen starting to channel Alan Greenspan

Janet Yellen isn’t gutsy enough to say it as clearly as Alan Greenspan did more than 20 years ago.

But ­a few weeks ago, it was revealed that Yellen’s Fed, in one of the last policy meetings she will preside over, came close to speaking like Greenspan.

While the Fed was expressing largely optimistic views of the economy (as it always does), its board was worried that the financial markets’ rally was getting out of hand.

Members were concerned that what stocks are doing would endanger an economy that everyone hopes is not faking ­signs of life.

“In light of elevated asset valuations and low financial market volatility, several participants expressed concerns about a potential buildup of financial imbalances,” the Fed said in the minutes of its Oct. 31-Nov. 1 meeting.

Stocks have gone up even further since then.

“They worried that a sharp reversal in asset prices could have damaging effects on the economy,” according to the minutes.

Greenspan made his “irrational exuberance” comments in 1996. It took a few years after the comments for the dot.com bubble to burst — but the stock market did eventually crash.

“Elevated asset valuations” is how this Fed is expressing its concern, probably because “irrational exuberance” is already taken.

But the problem of a frothy stock market and the cause are the same.

During the early 2000s, Greenspan took the Fed into uncharted territory when he lowered interest rates rapidly and vigorously.

You can credit the ­bursting of the dot-com bubble for that. Greenspan needed to make sure the resulting decline of the stock market didn’t happen at a precipitous pace.

And Greenspan never really had time to adjust them up again because there was soon a terrorist attack in 2001 that required the maintenance of easy credit conditions.

Rates stayed low because of ­ 9/11 ­and went even lower when the Great Recession hit and the Fed, then under Ben Bernanke, decided to experiment with quantitative easing, a policy that is only now — a decade later — being unwound.

Fed bosses don’t ever say the word “bubble” because it might lead to a crash during their term. When the next person takes over, honesty is more forthcoming.

Yellen leaves office in February, when Jerome Powell is due ­to take over. Then we will know what she really thinks — and we probably won’t be able to shut her up ever again.

Greenspan is still talking. In an interview on CNBC in August, he warned that a bubble — the one in the bond market — was getting set to burst. “The current level of interest rates is abnormally low and there’s only one direction in which it can go, and when they start, they will be rather rapid,” Greenspan said.

Let me translate. Bond prices move in the opposite direction as interest rates. So when rates rise — something the Fed is trying to make happen — then the price of bonds will automatically decline.

But here is what was unsaid: when rates rise — rapidly or not — they hurt corporate profits. And when corporate profits are jeopardized, then stock prices will also fall.

So in predicting the end of the bond market bubble, Greenspan and everyone else is also saying that the stock market is also in danger.

There are two things that can save bonds: An economy that’s growing slowly enough not to aggravate inflation or a Fed that doesn’t give a hoot about inflation or the value of the dollar. But if the Fed ignores its main mandate, which is to protect the dollar’s value and control inflation, we will have many more problems than we think.