One of two groups in the running to renovate Seattle's KeyArena pulled out Sunday night.

Seattle Partners, a partnership comprised of arena giant AEG and Hudson Pacific Properties, announced it will no longer pursue rights to the renovation.

"We remain firm in the belief that our proposal best serves the people of Seattle, but, unfortunately, significant factors through the bidding process have eroded our confidence in the ultimate execution of this project, no matter which group is selected," the partners wrote in a letter in Seattle mayor Ed Murray.

The AEG/HPP group submitted a bid in April to privately finance the renovation for $521 million, according to The Associated Press.

Oak View Group, the apparent favorite in the process, put forth a $564-million plan and is expected to be selected by Murray to oversee the project this week, according to Geoff Baker of the Seattle Times.

The letter to the mayor cites a fear that "the city is driving toward an unrealistic financing structure," and expresses concern that the city didn't conduct "a sufficiently thorough, objective and transparent process to properly evaluate the respective strengths and weaknesses of the two proposals, and most significantly, to identify the proposal best positioned to deliver a project consistent with the community's interests."

Specifically, the AEG/HPP group criticized the city for withholding "critical financial portions" of the Oak View Group's proposal from the public while sharing theirs with their full support, saying that act raised "serious questions about the integrity of the decision-making process and the ability of the public to make fair and equitable comparison."

Oak View Group is led by former AEG president and CEO Tim Leiweke, who later held those same titles with Toronto-based Maple Leaf Sports and Entertainment before forming OVG with MSG and Live Nation.

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