Sam Katz, a Mount Airy-based millionaire, has changed his party affiliation from Republican to independent, KYW reported Thursday morning.

The former — and potentially future — mayoral candidate later tweeted the reasoning behind the change in party affiliation.

The move is very likely presaging a fourth run for mayor by Katz against the winner of May's Democratic primary. Katz made millions in finance, served in Mayor Bill Green's administration as finance director, and narrowly lost to John Street in the 2003 mayor's race. He has since been working as a producer at History Making Productions, a local film company.

Asked if the party switch was a signal of his mayoral ambitions, Katz said in an email, "I ran for mayor in 1991, 1999 and 2003. I registered Independent in 2007 and considered it and gave some thought to running against Nutter in 2011 in the primary. These are reported facts. I guess I don't see any question about ambition?"

As the Inquirer reported last month, Katz' party affiliation has been in flux for years. He has run as a Republican in his two most-recent mayoral campaigns, but switched to Democrat in 2008, before switching back to Republican four years later.

Although Katz added that, for now, he is still not committing to a run, he will release a statement about school funding in the coming weeks, and launch a website to articulate his "ideas" for improving the city.

"I'm going to have things I want to say, and this provides me a platform to say them," he said, hinting that the website could be converted for campaign purposes down the road.

Katz said he would focus on his ideas for tackling Philadelphia's poverty rate, educational crisis, unsolved violent crime, and, of course, jobs.

"Job performance has been quite weak," he said. "The tax structure and regulatory environment and the noises that come out of City Hall about job creation and how employers are treated is a powerful message."

If he did become a candidate for November's general election, Katz would likely have a tough road to hoe. The last independently affiliated mayor of Philadelphia was Rudolph Blankenburg, elected in 1911.