Ryan Busse in The Missoulian

On Gun Control: Left gun industry frustrated about marketing assault rifles

Their main source of income prior to 2020 was firearms company Kimber Manufacturing, where Busse served as vice president. The bulk of their income in recent years came from Aspen Communications, a public relations firm run by Swan-Busse.

Gianforte obtained massive wealth though the 2011 sale of his Bozeman, Montana-based software company, RightNow Technologies, to Oracle Corp. His income over the past decade primarily came from profits on investments and averaged more than $6 million annually, according to his returns. He is paid about $120,000 a year for being governor.

On Tax Reform: Released his tax returns publicly, to ensure debate occurs

The release of the tax records comes after Gianforte last week dismissed Busse as not a "serious candidate" and suggested he wouldn't debate him since the Democrat had not released his tax returns. "It's a complete charade," Busse told AP after providing his returns. "If this is the singular reason why Gianforte will not debate, I'm not going to let him have that excuse."

Last week, [Gianforte's campaign wrote] a memo to reporters that Gianforte was prepared to debate a credible candidate but suggested that was not Busse. "The first step to getting a debate is we need a serious candidate who releases his tax returns just like every other candidate has done, and then we can talk about scheduling a debate," Gianforte said in an Aug. 28 interview with KECI-TV in Missoula.