Dow Jones industrial average (INDU), S&P 500 (SPX) and Nasdaq (COMP) futures were down ahead of the opening bell. Futures measure current index values against perceived future performance.
On Friday, stocks dropped after a court ruled against Wells Fargo and U.S. Bancorp in a foreclosure case. The ruling sparked a selloff in bank stocks that rippled through the broader market.
The government's latest reading on the labor market also dragged markets lower. The U.S. economy added slightly fewer-than-expected jobs in December, but the unemployment rate edged lower than economists had anticipated.
That disappointment may continue to trickle into trading this week, said David Jones, chief market strategist at IG Markets.
"There's still an air of caution after the payroll data on Friday," Jones said. "The market had factored in a good number, so anything less than expected is always going to be a disappointment, and shows what a problem U.S. employment really still is going forward."
World markets: European markets fell in morning trading, amid talk that Portugal is being pressured to take a bailout package to stop the spread of eurozone debt. Investors are also preparing for government bond auctions in Portugal, Spain and Italy this week.
"Markets are worrying that the European debt crisis is coming back again," Jones said. "[Portugal] is denying that they need [a bailout], but we saw that with Greece and Ireland as well before they got bailouts."
Britain's FTSE 100 edged down 0.5%, the DAX in Germany lost 1% and France's CAC 40 dropped 1.6%.
Asian markets ended the session lower. The Shanghai Composite fell 1.7% and the Hang Seng in Hong Kong slipped 0.7%. Japan's Nikkei was closed for holiday.
Companies: Shares of Sara Lee (SLE, Fortune 500) jumped nearly 7% in pre-market trading on reports that Apollo Global Management and other private equity firms are looking into acquiring the food company.
Chemical maker DuPont (DD, Fortune 500) said Sunday it will buy Danisco, a Danish enzyme and food ingredients company, for $5.8 billion in cash. Shares of DuPont edged slightly lower in early trading.
Shares of Progress Energy (PGN, Fortune 500) rose more than 2% before the opening bell, after Duke Energy (DUK, Fortune 500) said it will buy the fellow power company for $13.7 billion in stock.
Stocks brace for earnings test
After markets close, Alcoa (AA, Fortune 500) will release its quarterly results, the first of the Dow components to report its fourth-quarter figures. The aluminum maker is expected to announced earnings per share of 19 cents, according to analysts surveyed by Thomson Reuters.