There's scary message for China bulls in financial firms' issues

Declines may signal a 'temporary peak of the broad market' for stocks

Chinese mainland stock bulls may want to take note of the sell-off in financial shares.

If recent history is a guide, the losses in the CSI 300 Financials Index - which total 8.1 percent since the start of the year compared with a 1.7 percent gain in the CSI 300 Index - are signaling that the world-beating rally in Chinese equities could be about to come to an abrupt, and painful, end. The last time the industry lagged behind the broader market by this much in November 2007 and August 2009, the CSI 300 Index lost an average 42 percent over the following 12 months.