Are we about to see U.S. stocks take a significant tumble?  If you are looking for a “canary in the coal mine” for the U.S. stock market, just look at high yield bonds. In recent years, almost every single time junk bonds have declined substantially there has been a notable stock market correction as well.  And right now high yield bonds are steadily moving lower. 

The biggest reason for this is falling oil prices.  As I wrote about the other day, energy companies now account for about 20 percent of the high yield bond market.  As the price of oil falls, investors are understandably becoming concerned about the future prospects of those companies and are dumping their bonds.  What is happening cannot be described as a “crash” just yet, but there has been a pretty sizable decline for junk bonds over the past month.  And as I noted above, junk bonds and stocks usually move in tandem. In fact, junk bonds usually start falling before stocks do.  So does the decline in high yield bonds that we are witnessing at the moment indicate that we are on the verge of a significant stock market correction?

That is a question that CNBC asked in a recent article entitled “Near perfect sell signal says stocks should drop“…

The S&P 500 and the iShares iBoxx High Yield Corporate Bond ETF are a mirror image since the start of the year, but since the end of October, high yield has diverged to the lower right, and yet the S&P 500 has continued to record highs. Since separating in October, the S&P 500 is up 3 percent, while the high-yield ETF is down 4 percent.

On 10 occasions since 2007, the high-yield ETF dropped 5 percent in 30 trading days. During nine of those instances, the S&P 500 fell as well, with an average return of negative 9 percent, according to CNBC analysis using Kensho.

Only once did high yield give a false sell signal. That was last year, when the market was already entranced by the Federal Reserve's quantitative easing program, which has seemed to elevate stocks with an abnormal consistency. And even then, the S&P 500 managed just a 0.4 percent climb amid the junk debt rout.