In a recent note to clients, the members of the strategy team at Credit Suisse outlined all the reasons they are looking for a period of weakness in the stock market, not unlike the multi-month swoon seen last summer. They point to a big drop in new orders in the service sector, rising jobless claims, falling interest rates on Treasury bonds, a fall in copper prices and underperformance of small stocks as reasons for worry.

The strategy team at Société Générale led by Albert Edwards goes even further, suggesting that our current situation resembles the post-bubble, debt-deflation aftermath suffered by the Japanese in the 1990s. He points to a sharp drop in the growth rate of orders of durable goods (fewer aircraft and defensive goods), a stalling of corporate profits as measured by the government and a downturn in optimism by stock market analysts.

Given all this, and unattractive valuations, Edwards notes that "this is the point in the cycle when investors should be becoming more cautious."