Former U.S. Secretary of State Hillary Rodham Clinton speaks at a Winnipeg Chamber of Commerce luncheon on Jan. 21. (John Woods/AP)

Hillary Rodham Clinton’s decision to delay an announcement about her presidential ambitions until as late as July has stymied efforts of a major allied super PAC to come out of the gate early with a slew of big-money commitments.

Priorities USA Action — which has positioned itself as the main advertising vehicle to back a Clinton candidacy — had hoped to line up dozens of seven-figure pledges before April as a show of strength but has secured only about 10, according to people familiar with the situation.

One factor that has contributed to the reluctance: Many wealthy political givers on the left have written large checks to the Bill, Hillary and Chelsea Clinton Foundation, part a drive to raise money for the nonprofit organization before a likely Clinton presidential run. Major foundation donors have indicated to ­super-PAC fundraisers that they are holding off on other large pledges for now, according to people with knowledge of the conversations.

Priorities’ slow progress has prompted internal conversations about whether the group will recalibrate what it can expect to raise this cycle — a sum that people close to the operation originally expected to be around $300 million. The super PAC’s difficulties in securing pledges were first reported late Tuesday by Politico.

Priorities officials said they are not concerned.

“Priorities USA Action chose not to raise money in the 2014 cycle because we did not want to compete with the many good Democrats who were fighting for their political lives,” senior adviser Paul Begala said in a statement. “We will play a critical role in electing a Democratic President in 2016. Anyone who doubts us should ask President Romney.”

Many party fundraisers concur, saying that once Clinton is officially in the race, the money will rush in from loyalists and new donors eager to be part of her candidacy.

“I think it’s like everything else going on -- what’s the timeline with her?” said one party strategist familiar with the dynamics, who requested anonymity to discuss donor attitudes. “Once things are more finalized with what she is doing, their job will become a little easier.”

Some top Democratic contributors said they won’t consider committing large amounts until she is officially in the race.

“I’m waiting to see if Hillary announces a campaign and to see what it looks like,” said David desJardins, San Francisco-based investor who supports independent political groups on the left.

Among the major Clinton supporters who have not pledged to Priorities is Esprit co-founder Susie Tompkins Buell, according to a person familiar with the situation. Buell, an early backer of the group Ready for Hillary, did not return a request for comment.

Billionaire media mogul Haim Saban, who has said he will spend “whatever it takes” to help Clinton reach the White House, has also not made a commitment to the super PAC, according to a person with knowledge of the fundraising efforts. Saban and his family have given between $10 million and $25 million to the Clinton Foundation, including a donation last year, according to the foundation’s records. A spokeswoman for Saban could not immediately be reached for comment.

The difficulties that Priorities has encountered in assembling an early money juggernaut also suggests that Democrats are still working to overcome distaste in the donor community for big-money groups.

New York venture capitalist Alan Patricof, a longtime Clinton friend and fundraiser, said he does not plan to get involved until she is an official candidate — and at that point, he said, he will probably focus his efforts on helping her official campaign.

“I am not much interested in a super PAC,” he said. “It’s just not something I believe in. I’m not ready to deal with the realities that people can give any amount of money.”

The early donor drought is one of the factors that led to a public falling-out this week between liberal activist David Brock and Priorities officials. Brock, who runs a network of prominent groups on the left such as Media Matter and American Bridge, noisily resigned from the super PAC’s board Monday, accusing people affiliated with the group of feeding negative information to the New York Times about the fundraising practices of his organizations.

After outreach by top Priorities officials, Brock agreed to reconsider joining the group. But the public showdown exposed a clash between two power spheres on the left, both vying for big contributions.

Supporters of Priorities were hoping to build an early financial base and avoid scrambling for dollars in the midst of the campaign, as the group did during the 2012 race, when the nascent super PAC initially struggled to raise money to run ads on behalf of President Obama.

In the end, Priorities pulled in $79 million. While the group was far outpaced by the pro-Mitt Romney super PAC Restore Our Future, which raised $153 million, its hard-hitting ads were credited with helping frame the Republican presidential nominee as an out-of-touch plutocrat.

This time around, the donor outreach began early. The day after last November’s elections, DreamWorks Animation chief executive Jeffrey Katzenberg and Hollywood political strategist Andy Spahn began reaching out to potential backers, urging them to make commitments to Priorities, which was refashioned into a pro-Clinton vehicle after 2012.

Other top officials have also been making pitches, including Priorities board co-chair and former Michigan governor Jennifer Granholm, executive director Buffy Wicks, finance adviser Jonathan Mantz, and senior advisers Sean Sweeney and Begala.

Less involved has been Jim Messina, who ran President Obama’s reelection campaign and co-chairs Priorities with Granholm. Most recently, he has been in London, where he has been consulting for Prime Minister David Cameron in the run-up to British elections.