Research in Motion Inc. said Wednesday it is making a $66 million unsolicited takeover bid for Canadian software company Certicom Corp., one day after the maker of Blackberry devices cut its own sales forecast.

Certicom "is a natural fit for RIM," said Jim Balsillie, co-chief executive officer of the Waterloo-based company.

The bid of $1.50 a share represented a 76 per cent premium over Certicom's Dec. 2 closing price of 85 cents.

Certicom rose 74 cents to $1.59 in TSX trading. 

Certicom, which has offices in Toronto and Reston, Va., makes encryption software for all sorts of devices, including RIM's popular handheld offering.

Balsillie said RIM has tried to talk to Certicom's management about a possible takeover but received no response.

 "As we are unable to engage Certicom management in a meaningful dialogue to advance the terms of a potential transaction, we believe it is in the best interests of our respective shareholders, employees and customers to make this attractive offer directly to Certicom shareholders now," he said in a press release.

Certicom's shares topped out at $1.16 as its highest price since Oct. 22.  The company, which had not responded to RIM's bid, plans to release its second-quarter earnings after the close of trading on Wednesday.

RIM made the bid after cutting its third quarter sales forecast on Tuesday.  The company said it now expects sales to range between $2.75 billion US and $2.78 billion US, down from previous estimates of $2.95 billion US and $3.10 billion US  for the same three months.

RIM, which fell $3.75 to $46.46 on Tuesday, rebounded Wednesday, adding $2.44 to $48.90.