Warnings about an imminent collapse of developed economy stock markets, especially the U.S. markets, are everywhere. Whether you use Shiller’s CAPE ratio, Buffett’s preferred market-cap-to-GDP ratio, or traditional P/E ratios, markets seem overpriced and ready to fall.

Of course, that does not mean they will fall anytime soon. As we saw in the dot.com bubble of 1996-2000, and the housing bubble of 2002-2007, so-called “irrational exuberance” can last longer than the skeptics believe. However, some warnings perhaps deserve more attention than others.

The warnings I pay most attention to are those from establishment insiders. These are the kinds of individuals who attend Davos and routinely discuss market conditions with central bank heads, finance ministers and people like Christine Lagarde, head of the IMF. The credibility of such insiders is enhanced ever further when they come with serious academic credentials such as an economics Ph.D. from a top university in the field.

William White is such an individual. He was former head of the OECD review board and former chief-economist for the BIS, the “central bankers central bank” based in Basle, Switzerland. This article is an interview with White in which he flatly declares, “All the market indicators right now look very similar to what we saw before the Lehman crisis, but the lesson has somehow been forgotten.”

You can’t get much more of a blinking red light than that. Smart investors should prepare now with reduced exposure to stocks and increased allocations to cash and gold.