According to the IMF most banking crises happen in the month of September. The IMF analysed 147 banking crises from 1970 to 2011 in countries around the world and when they began: September is the standout month. There have been 25 crises that had their origins in September. December was in second place with just seven.

Why? No specific reasons are given but The Economist cites the fact that autumn is the time when farmers need to borrow money to bring in the harvest, which strained reserve banking systems. Then there is the October fiscal year end of American mutual funds; managers trying to avoid losses or hold on to gains for the year are more likely to do something towards the year end date. However that would not explain the pattern occurring in other countries that have different year ends.
I think it has more to do with holidays. 

You remember the old stock market adage: “sell in May and go away”. People return from holiday and feel compelled to do something and what was put off before the holiday has to be done now. 
The famous economist Kenneth Rogoff offers a better explanation. He reckons crises happen in election years and cites Mexico (1982 and 1994), Korea (1998), USA (2008), and Greece (2009).
The reason is that balances accrue over a long period of time and politicians have a strong incentive to get re-elected and try to delay the inevitable. In Greece they actually hid the truth until the polls had closed!
We have just had an election in Spain and the economic truth emerged just after the result. We are still waiting to see the real economic picture emerge in France after its recent election.
But the big ones to come are the US elections in November 2012 and the handover of power at the CCP National Congress in PR China in October 2012.
Have a great relaxing summer holiday because it could be a turbulent autumn. 

Warwick Bartlett, GBGC Chief Executive