I mean, really. This is getting ridiculous.

On Wednesday, stocks were probing new all-time highs. Then in the afternoon, word came out that Alan Greenspan had given a speech somewhere or other in which he supposedly said that the Chinese stock market was poised for a "dramatic contraction." That's all it took. Within minutes, U.S. stocks were trading lower. The S&P 500 closed without exceeding its historic 2000 peak.

And all because an octogenarian who used to be the chairman of the Federal Reserve ? but is now, well, nothing ? said that Chinese stocks would go down someday.

Does it take a genius to say that? Is it even news? Chinese stocks have been on a speculative rampage over the last year. Everyone knows that. And everyone knows that they are going to correct hard sooner or later.

What does that have to do with the U.S. stock market anyway?

Nothing. But "the Maestro" said it. So it's automatically important.

Let's get real here.

There used to be a time when investors had to listen to Alan Greenspan whether they wanted to or not. Investors had to sit through his endless monotone lectures on whatever subject he chose to pontificate about. Monetary policy, the economy ? sure, he was Fed chairman. But you couldn't stop the guy from talking. About education. Regulation. Trade. Taxes. You name it.

But, hey, when the Fed chairman talks, you listen. After all, he's the guy with his hand on the printing press that prints the money in this country. Even if he's droning on about what kind of coffee he prefers at Starbucks, you listen. He might just say something about interest rates.

But truth be told, when it comes to predicting the stock market, Alan Greenspan was as bad as they come.

Remember his famous warning about "irrational exuberance"? According to most people's memories, that made Greenspan a genius. Remember Nasdaq 5000? Boy, was Greenspan ever right.

Well, no. As a matter of fact, he was completely wrong.

He didn't give that warning in March 2000 when you could have made money getting out of stocks. He gave that warning in a speech on Dec. 5, 1996. The S&P lost 3% in the 10 days after that speech.

But stocks never traded lower again. Ever. Not ever.

By the S&P 500's top in 2000, stocks were up 116% from when Greenspan warned of "irrational exuberance."

Great call, huh? Just think. If you'd heeded the Maestro's advice, you could have missed a 216% gain. Lucky you.

Yes, I know. Stocks fell hard after that. But even at the lows of the post-bubble bear market in 2002, the S&P 500 was still 13.4% higher than when Greenspan said to get out. Even then, Greenspan was still wrong.

Suppose you'd bought stocks ? not sold them ? when Greenspan warned of "irrational exuberance" and held them through today? With dividends included (as is the case for all the returns I've cited), you'd be up 139%.

Aren't you glad you didn't listen to Alan Greenspan then? (You did listen to him? Well ? aren't you sorry?)

So then why would you listen to him now?

It doesn't impress me one bit that Greenspan is now working for the giant fund manager Pimco, as a "special consultant," side by side with famous bond guru Bill Gross.

Gross's record at predicting the stock market is almost as bad as Greenspan's. In September 2002, just weeks before the very bottom of the post-bubble bear market, when the Dow Jones Industrial Average traded below 7300, Gross warned that the Dow was headed for 5000. That's a 31% drop from where the Dow was then.

You know how it turned out. Gross's dire prediction marked one of the greatest buying opportunities in market history. Since the bottom, instead of falling 32%, the Dow rose 84% (that's not including dividends).

Gross manages the biggest bond fund ever. But he's been dead wrong about the direction of interest rates for the last two-plus years, calling for them to fall while the Fed relentless hiked and hiked and hiked. In a memo to clients this month, Gross admitted he was wrong (sort of ? it "cost us some basis points," he said). And then he turned around and predicted once again that rates would fall.

So now Greenspan and Gross are working together. A publicity bonanza? To be sure. But in terms of predicting the market, it's more like a suicide pact.

I started this column with a question: Will Alan Greenspan please shut up? I know the answer to that one. It's "no."

So let me ask a more useful question. Will you please stop listening to Alan Greenspan?

I have.