Denver Mayor Michael Hancock filed paperwork that made his re-election bid official Monday, while reporting that his campaign war chest continues to grow fat.

Hancock, seeking a third term, has been picking up opponents, including former state Sen. Penfield Tate III last week and Regis University professor Lisa Calderon on Monday, along with others.

From July through September, he raised $184,379 to go along with $528,454 he had raised previously. That gives him $712,833 to take on newcomers before next May’s election. After expenses, the campaign has a $670,000 head start on newcomers to the race.

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The campaign noted that among its 359 contributors are former mayor turned governor John Hickenlooper, Lt. Gov. Donna Lynne and the Denver Fire Fighters Union.

“We are proud of the growing support for Mayor Hancock’s re-election,” said his campaign spokesman, Jake Martin, in a statement. “Under his leadership, Denver is now one of the best cities to live, work and play. We’re excited for the upcoming campaign to highlight the mayor’s solid plans and clear vision to keep our city moving forward and ensure our success extends to everyone, in every neighborhood.”

Hancock won a four-way election with more than 80 percent of the vote in 2015. He won the office in 2011 against Chris Romer, 58 percent to 42 percent.

Romer, the son of former Colorado Gov. Roy Romer, raised almost $2.6 million to Hancock’s $1.5 million.