Struggling to maintain poise

LONDON (CNNMoney.com) -- U.S. stocks appeared set for a tough open Wednesday as investors struggled to maintain their poise in the face of ongoing credit problems and a heavy economic calendar.

At 5:31 a.m. ET, Nasdaq and S&P futures were lower, although well off earlier lows.

Stocks advanced Tuesday, recovering from a sell-off that sent stocks into a correction earlier in the week. Markets got a boost after Abu Dhabi's investment arm injected $7.5 billion into troubled bank Citigroup (Charts, Fortune 500).

But the recovery could be short-lived following more news of credit woes. Wells Fargo (Charts, Fortune 500) said late Tuesday it would take a a $1.4 billion provision in the fourth quarter for loan losses. Freddie Mac (Charts, Fortune 500) also said it would sell $6 billion of stock to bolster its finances.

A batch of economic reports are due Wednesday, include durable orders, existing home sales and the Fed's Beige Book of economic conditions.

In addition, the government is set to release its weekly report on fuel inventories. Oil prices tumbled more than $3 Tuesday on growing expectations for OPEC to boost production. Light, sweet crude for January delivery fell 38 cents to $94.04 a barrel in electronic trading early Wednesday.

Stocks in the cable sector, including Comcast (Charts) and Time Warner Cable (Charts), are in focus after federal regulators said they would collect more cable subscriber data before determining whether to expand oversight of the industry.

In global trade, most markets in Asia finished the session lower, and European stocks advanced in morning trading.