Newly published election spending figures show Sarah Palin ended the last quarter with a war chest of more than $1m, suggesting gathering momentum for a run at the White House in 2012.

Her political action committee, a body for raising and distributing election cash, raised $866,000 in the three months from April 1, the most since it was formed in January 2009. She spent about $742,000 over the quarter, most of it on building up her political profile and base support.

Palin, who enjoys the support of the Tea Party and other grassroots activists but is distrusted by the Republican party establishment, has not yet said whether she will stand as a candidate. She and other potential rivals for the Republican nomination would normally begin to make their intentions clear early next year, in the wake of November's Congressional mid-term elections.

But a breakdown of money raised and spent by Palin suggests she is putting in place the political framework for a bid. She spent almost twice as much as in any previous quarter, much of it on speechwriters, private jets for public appearances, and hiring consultants to advise her on domestic and foreign policy, which were embarrassing weaknesses during her vice-presidential run in 2008.

She is also taking on more staff, including for the first time someone to keep control of her schedule. Until now, her organisation has tended to be chaotic.

John Ellis, a conservative political analyst, predicted she would be the de facto Republican frontrunner by December and that, by then, it may be too late for the party to do anything about it. Ellis wrote on his blogsite: "'She's too stupid' is what the Establishment GOP really thinks about Sarah Palin. 'Good-looking,' but a 'ditz'. This is unfertile ground, since Palin can turn the argument on a dime and say: 'They drive the country into bankruptcy, they underwrite Fannie and Freddie, they bail out Goldman Sachs, they fight wars they don't want to win, they say enforcing the immigration laws is silly and they call me stupid! I'll give you a choice: you can have their smarts or my stupidity, which one do you want?' A large number of GOP presidential primary voters will take Palin's "stupidity" in a heartbeat."

Palin's potential Republican rivals, who have also set up PACs, include Mitt Romney, the multi-millionaire and former governor of Massachusetts who was John McCain's closest competitor for the Republican nomination in 2008, Mike Huckabee, the former governor of Arkansas who has a strong following among evangelical Christians, and Tim Pawlenty, governor of Minnesota.

Small donors have contributed substantially to Palin's funds, reflecting her grassroots support. Tim Crawford, the PAC treasurer, told the Politico website that 8,000 new donors have been added in the last quarter, bringing the total of contributors to 25,000.

"Essentially when we started last January, we started from scratch," Crawford said. "We didn't have a big base of people coming out of the presidential campaign. Everybody knew that there was this massive amount of support, but she didn't have it, because all that stuff was property of the McCain campaign. But now, I think we've got a pretty formidable thing going on, and it grows every day."

As well as spending on building her own support, Palin distributed $87,500 in the last quarter to Republican candidates she is backing in the elections for Congress and governorships in November.