An activist Research In Motion investor says holders of at least 8 percent of the BlackBerry maker's stock back its call for a sale or a corporate shake-up at the struggling Canadian company.

Jaguar Financial Corp said it expects the percentage of RIM stock that supports its position to keep rising as it talks with more institutional shareholders about joining its campaign for sweeping change.

Our supportive shareholders approve Jaguar's plan to negotiate, at this point in time, changes in governance and the pursuit of a value creation transaction, Jaguar Chief Executive Vic Alboini told Reuters on Tuesday.

Shares of RIM, which makes the BlackBerry smartphone and Playbook tablet computer, have been battered this year, reflecting a steady erosion of market share to devices made by Apple or powered by Google's Android software.

Jaguar, a Canadian merchant bank that targets underperforming companies, wants RIM to hire a new chief executive to replace current co-CEOs Mike Lazaridis and Jim Balsillie, and to put itself up for sale, either as a whole or in parts.

With 8 percent support Jaguar could demand a shareholders meeting, ratcheting up the pressure on RIM's board and management to address its demands, Alboini said.

RIM said at its annual meeting in July that holders of more than 90 percent of its voting shares had backed the reelection of a slate of directors that includes the co-CEOs.

RIM could not be reached for immediate comment on Tuesday.

Stock in the company hit a 52-week low of $19.29 a share on the Nasdaq on October 4, less than a third the C$70.54/share high it touched in February.

Alboini said a reasonable range for RIM's stock valuation would be between C$40 and C$60/share, depending on the nature of any change fostered at the company.

Everybody is in support of a sale of RIM or another value creative transaction, Alboini said. Like splitting the company into separate public companies - a network company, a device company and a patents company.

Alboini said Jaguar's campaign for a shake-up at RIM would gather steam as talks with other institutional shareholders deepened. He said Jaguar had so far only spoken to about 20 of the larger institutional holders, compared with the more than 1,000 investment managers listed by Thomson One as stockholders.

We haven't adopted a call-center approach, he said. It has been very highly targeted, but now that we've got the response, you know we are going to go out and see how many more we can get.

Alboini said he had not been in contact with activist investor Carl Icahn and could not confirm speculation in recent weeks that Icahn might take a stake in RIM.

Alboini says RIM's leaders have lost their way in competing in a technology landscape that has changed dramatically, forcing it to play catch-up to the likes of Apple, Google, Microsoft, Samsung Electronics and HTC.

It is time for RIM to bring in a transformational leader and a respected independent chairman, said Alboini, who has accumulated more shares of RIM since its stock price plunge.

(Reporting by Pav Jordan and Alastair Sharp in Toronto; editing by Janet Guttsman and Frank McGurty)

Apple inc. Blackberry