European stocks rallied on Wednesday, led by Spanish, Italian and Greek shares after Germany's Constitutional Court said the country can ratify the euro zone's new rescue fund and budget pact as long it can guarantee there will be no increase in German financial exposure to the bailout fund without parliament's approval.

Apple Inc (AAPL.O) will be in focus on Wednesday as the company is set to unveil its newest iPhone, which is widely expected to offer 4G wireless technology for the first time, and a 4-inch display, up from the current 3.5 inches.

Shares in Samsung Electronics (005930.KS) rose more than 3 percent to their highest intraday levels in more than three weeks on Wednesday, shrugging off rival Apple Inc's (AAPL.O) planned unveiling of its newest iPhone.

Facebook Inc (FB.O) will also be in the spotlight after CEO Mark Zuckerberg soothed investors in his first major public appearance since the No. 1 social network's rocky May IPO, breathing life into its struggling shares after hinting at new growth areas from mobile to search. His comments helped drive Facebook shares up more than 3 percent after hours to above $20, building on a 3.3 percent gain in regular trade on Tuesday. The stock is still well off its $38 debut price.

Ford Motor Co's (F.N) board of directors will discuss this week a succession plan for Chief Executive Alan Mulally, who is expected to retire by the end of 2013, Bloomberg reported on Tuesday, citing a person familiar with the matter.

On the macro side, investors awaited wholesale inventories for July, while keeping an eye on the Federal Open Market Committee, which begins its two-day meeting on interest rate policy.

The Dow industrials closed at the highest level in nearly five years on Tuesday in a lightly traded session before the key decisions in Germany and the United States, which could give markets a further boost.

The Dow Jones industrial average .DJI ended up 69.07 points, or 0.52 percent, to 13,323.36. The Standard & Poor's 500 Index .SPX closed up 4.48 points, or 0.31 percent, to 1,433.56. The Nasdaq Composite Index .IXIC gained 0.50 point, or 0.02 percent, to 3,104.53.

(Reporting by Blaise Robinson; Editing by Catherine Evans)

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