Why is it that financial crises often happen in October?

Trawling through the pages of the Guardian on Friday, a diligent reader might have come across a news item about a US hedge fund by the name of Refco: "World's hedge funds face crisis as Refco suspends trading". Refco? Why, it was only a couple of months ago that:

On August 16, Refco proudly announced the completion of its flotation in New York. At an issue price of $US22 a share (£12.50), the company was valued at $US3.4bn. The cream of Wall Street's investment banks - and the odd European wannabe - handled the share sale: names such as Goldman Sachs, Deutsche Bank, JP Morgan, Merrill Lynch, Bank of America and Credit Suisse First Boston. Refco says it is the world's largest futures broker with 450 traders in offices around the world. As evidence of its market power, the firm announced this year that in the three months to the end of February, Refco's volume in the foreign exchange market alone was $US111bn.

Turns out there was some jiggery-pokery going on to the tune of a 'loss' of at least US$430m (£250m). The investigators have piled in, computers seized, someone is now out on bail of US$50 million. Shares in the company dropped to US$7.90 before trading was halted. Because finance capital is highly leveraged, interconnected, interdependent, the major players are now in a major panic, fearing a knock-on effect.
Dealing in arcane financial 'instruments', fortunes can be won and lost in a jiffy in casino capitalism.
Not my money, who cares?
The problem is, it isn't only the beat of a butterfly's wings in the Amazon forest that can have repercussions on the other side of the world. This sort of financial collapse can, and may, cascade and ricochet through the world's financial systems leading to other companies collapsing, banks tightening up on their lending, interest rates rising. In short, we innocent bystanders, we lesser mortals, may suffer grievously, while the fat cats merely nurse their wounds. Well, they will do so as long as we let them do it. Until, that is, we see them off with pitchforks, scythes, and braziers.