NEW YORK ( TheStreet) -- Mitt Romney raised $18.3 million for the second quarter of 2011 ended June 30, his campaign announced on Wednesday.

The report officially establishes Romney as the clear front-runner among all Republican candidates as he out-raised the estimated combined second-quarter totals of Rep. Ron Paul (R., Texas) ($4.5 million), former Minnesota Gov. Tim Pawlenty ($4.2 million) and former Utah Gov. Jon Huntsman ($4.1 million).

"Voters are responding to Mitt Romney's message that President Obama's policies have failed and that we need new leadership in Washington," said Spencer Zwick, Romney's finance chairman. "Our fundraising for the second quarter represents the strong support Mitt Romney has across the country."

Romney's campaign reported that the former Massachusetts governor has $12.6 million in cash on hand.

All presidential candidates were required to submit their second-quarter contributions to the Federal Election Commission by the beginning of July. A spokesperson for the FEC said that campaign funds would be posted on its Web site by mid-July, unless a candidate filed for an extension.

-- Written by Joe Deaux in New York.

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