The bearish version, known as a "death cross," describes a situation where the price of a security moves beneath its short-term average, which also happens to be below its long-term equivalent.

As events would have it, choppy, range-bound trading early in the summer and the sharp sell-off that took place through mid-August have caused that latter pattern to start appearing in a number of different European markets.

In Italy, Switzerland, and Belgium, for instance, those countries' primary benchmark indices are currently trading below their respective 50-day averages; those averages, in turn, are beneath their respective 200-day equivalents.

Yet it is not just those three markets that are at risk. After only a few more days of share-price weakness, the mathematics suggest that many other European benchmarks, as well as the broader Dow Jones STOXX Index, will be in the same boat.

Moving average crossover methods, like most technically-based approaches, are not infallible. For one thing, they often generate loss-making "whipsaw" signals when markets are essentially treading water.

Regardless, the outbreak of bearish "death cross" signals that has been developing in European share markets lately lends credence to the notion that the broad-based bull market that began in 2002 may be nearing its end.

Michael Panzner is a 25-year veteran of the global stock, bond, and currency markets and the author of Financial Armageddon: Protecting Your Future from Four Impending Catastrophes and The New Laws of the Stock Market Jungle.