"What Cracks This Egg?" Morgan Stanley Asks, And Answers: "The Debt Ceiling Worries Us Most"

In the latest Sunday Start report from Morgan Stanley's Andrew Sheets, the bank's chief cross-asset strategist looks at the current state of the market - "the S&P 500, Russell 2000 and NASDAQ have hit all-time highs. Volatility has plunged back down near all-time lows. Credit is tighter and yields have been stable" - and asks the same question posed by virtually everyone else in recent weeks : "what rattles this market. What breaks the egg?"