U.S. stocks ended 2009 on Thursday with their best gains since 2003, with optimism about the economy’s recovery pushing the benchmark Standard & Poor’s index up 23.5 percent for the year.

Washington Mutual Inc said it could receive an additional $2.6 billion in tax refunds due to a recently enacted law, sending shares of the bankrupt bank holding company soaring on Thursday.

U.S. trucking giant YRC Worldwide said it averted bankruptcy by finally negotiating a critical debt-for-equity exchange that wipes out $470 million in debt and gives the struggling company access to needed credit as it restructures.

Pfizer Inc shares fell 1 percent on Thursday after it said a U.S. decision on whether to approve the company’s new version of its big-selling Prevnar vaccine that fights pneumonia and meningitis would push past the deadline.

World stocks mostly edged higher Thursday as traders headed into the long New Year holiday weekend in a fairly upbeat mood following a nine-month bull run that has seen many markets advance over 50 percent since March.

China imposed a tax Thursday on sales of previously nontradable shares in an apparent attempt to reassure investors by discouraging a possible flood of shares from entering the market and depressing prices.

The number of newly laid-off workers seeking unemployment benefits likely rose slightly last week, a sign that jobs remain scarce even as the economy slowly recovers.

Asia stocks rose on Thursday, racking up a 68 percent gain for the year, as a jump in U.S. consumer confidence reinforced views that the world’s largest economy is gradually recovering.

U.S. stocks ended a smidgen higher in very light trading on Wednesday as a stronger-than-expected report on Midwest U.S. business activity was offset by investors taking profits in some of the year’s better performers.

The government is providing a fresh $3.8 billion cash infusion to stabilize GMAC Financial Services as it struggles with hefty losses in its home mortgage unit.