While this indicator is generally not very good for picking tops (notice how long it remained mired below 15 during 2005 - 2007) it does serve to show how quickly Central Bank actions have eased investor worries. Notice the periods during which QEI and then QEII were underway and how that monetary easing sent the index lower. Investors were willing to ignore all the deep-seated structural issues ailing the Western economies (DEBT, DEBT and MORE DEBT, low employment, falling real estate prices, rising costs, etc.) as long as the Fed was keeping the money spigots open. NO WORRIES MATE - the FED HAS OUR BACK was the motto.
It will be interesting to see how this index responds as we move further into the year and as events unfold. It is generally true that there is a lull before the storm - we'll see.