Wall Street cautious as banks remain a concern ahead of Fed meeting.

Wall Street's main indexes are expected to open subdued as investors weigh a state-backed takeover of Credit Suisse and the odds of the Federal Reserve keeping interest rates unchanged this week. UBS agreed to buy rival Credit Suisse for $3.23 billion, in a shotgun merger engineered by Swiss authorities to avoid more market-shaking turmoil in global banking. U.S.-listed shares of Credit Suisse plummeted 57.9% in premarket and were set to open at a fresh record low, while those of UBS lost 3.5%. Traders' bets are now tilted towards a no-hike scenario, with 43% expecting the Fed to raise rates by 25 basis points.