Most U.S. stocks advanced, amid the cheapest valuation in six months for the Standard & Poor’s 500 Index, as an unexpected increase in a measure of service industries bolstered confidence in the world’s largest economy.

Equities reversed early losses today as the Institute for Supply Management’s index of non-manufacturing businesses, which covers about 90 percent of the economy, rose to 53.7 last month from April’s 53.5.

Finance ministers and central bank governors from the world’s leading economies agreed to coordinate their response to Europe’s financial crisis on a conference call that dealt with Spain and Greece. Spain called for outside support for the first time to battle the financial crisis as Budget Minister Cristobal Montoro said European institutions should help shore up the nation’s lenders.

JPMorgan (JPM) climbed 3.2 percent to $32. Hewlett-Packard (HPQ), the world’s largest personal- computer maker, rose 2 percent to $21.49. Homebuilder Lennar jumped 3.7 percent to $24.56, after slumping 13 percent in two days. PulteGroup increased 3.4 percent to $7.96.

SanDisk Corp. surged 5.3 percent, the most in the S&P 500, to $33.34. The company, which makes memory chips used in mobile devices, was rated outperform in new coverage at Pacific Crest Securities.

Starbucks dropped 3.6 percent to $51.97. The purchase of San Francisco-based Bay Bread and its La Boulange brand will decrease full-year profit by 2 cents a share, the Seattle-based company said in a statement yesterday. The French-themed bakery sells homemade granola, flank steak sandwiches and organic bread, according to its website.