Arsenal majority shareholder Stan Kroenke says his company KSE UK's shares in the club "are not, and never have been, for sale" in a statement to the Stock Exchange.
The American, who also owns NFL franchise Los Angeles Rams and MLS outfit Colorado Rapids, increased his shareholding at the Gunners to 67.05 per cent in May 2016 through his company Kroenke Sports Enterprise's purchase of 23 ordinary shares.
On Friday, Alisher Usmanov, who currently owns 30.04 per cent of Arsenal through his Red and White Holdings investment vehicle, made a £1bn bid to become majority shareholder of Arsenal.
Sky sources reported that the offer was expected to be turned down by Kroenke, and the 69-year-old tycoon confirmed on Monday he is not interested in selling any of his shares.
"KSE UK, Inc notes the recent media speculation concerning its shareholding in Arsenal Holdings PLC and confirms that its shares are not, and never have been, for sale," a statement read.
"KSE is a committed, long-term investor in Arsenal and will remain so."
Arsenal endured a disappointing campaign under Arsene Wenger, with the club failing to qualify for the Champions Leagues for the first time in the Frenchman's 21-year reign.
In addition to boardroom uncertainty, it has yet to be announced whether Wenger will remain beyond the current season with his contract expiring in the summer.
Uzbek-born Russian Usmanov, who has a personal fortune of around £11.2bn, has built his stake in the North London club since his initial investment in 2007.
"Some continuity is needed," Usmanov said in comments reported by Bloomberg last month. "This includes the need to prepare a successor for Wenger, but in a very respectful way. I can suggest that Wenger himself can prepare a successor."
On the pitch, the club face Chelsea in the FA Cup final at Wembley on Saturday.