ShoreTel's board of directors unanimously rejected Mitel's US$574 million takeover bid on Wednesday US time, calling the offer "highly inadequate".
The latest offer was for US$8.50 a share - US$8.10 in cash and 40 cents in Mitel common stock - and it followed a mid-October offer of US$8.10 a share, or about US$540 million. That offer was rejected late last month.
ShoreTel CEO Don Joos said in a statement that the company is better off without Mitel, a key competitor.
"We are confident that executing our strategic plan is the best path forward and will deliver substantially more value to ShoreTel stockholders than Mitel's significantly inadequate proposal," Doos said.
Mitel's merger offer was unsolicited. ShoreTel partners have been roundly sceptical about the proposed transaction and told CRN US that ShoreTel is the stronger vendor and Mitel's offering was "a joke".
Kristin Bent contributed to this story
This article originally appeared at crn.com