NORWALK, Connecticut and PALO ALTO, California — Xerox Holdings Corp. (NYSE: XRX) has threatened Hewlett Packard Inc. (NYSE: HPQ) with a hostile takeover effort, the latest development in a corporate merger that would include one of Fort Collins’ largest tech companies.

In a letter sent to HP executives Thursday afternoon, Xerox CEO John Visentin said his company was “surprised” at HP’s unanimous refusal towards Xerox’s $22 per share acquisition offer because its own financial advisor Goldman Sachs set a price target of $14.

Visentin also accused HP of asking for due diligence information from Xerox but not offering its own internal information to Xerox, which he called a delay tactic.

Xerox is demanding HP agree to mutual due diligence by 5 p.m. EST next Monday, or the printer firm will take its case directly to HP’s shareholders.

“The overwhelming support our offer will receive from HP shareholders should resolve any further doubts you have regarding the wisdom of swiftly moving forward to complete the transaction,” Visentin wrote.

HP rejected Xerox’s initial offer last Sunday, calling it “unsolicited” and an undervaluation of the computing giant. The offer was particularly unusual because Xerox, which reported $9.22 billion in revenue in the past 12 months, is significantly smaller than HP, which brought in $58.7 billion.