Why August is one of the most dangerous months in the financial calendar

Historically, crises have often erupted in late summer, which is why this week's mini crash set alarms ringing

Fears of a recession in the US. The biggest one-day fall on the Japanese stock market since 1987. Policymakers away on their summer breaks, leaving their deputies in charge. All familiar enough territory for August - one of the most dangerous months in the economic and financial calendar.

In theory, August should be a month when not much happens and often that is the case. Stock market trading volumes tend to be light and if August starts calm it will tend to stay calm. But bad things can happen and when they do they can have profound consequences.