Corporate raider Carl Icahn revamped his proposal Tuesday for embattled computer company Dell, calling for a big share buyback in a plan which would keep the company public. Icahn, who has lambasted a go-private plan led by founder Michael Dell as undervaluing the company, said he and his investor allies would vote against that proposal and urged shareholders to consider his alternative. Under his plan, Dell would make a tender offer for $14 per share for approximately 1.1 billion Dell shares.

By Alonso Soto BRASILIA (Reuters) - Moody's Investor Service says it will become more difficult to justify its "positive" outlook on Brazil's investment-grade credit rating if the country remains in the grip of weak economic growth and its debt burden fails to decline, a senior official from the ratings agency said.

By Susan Taylor TORONTO (Reuters) - Canada's Tim Hortons Inc <THI.TO> is under mounting pressure from activist investors to boost shareholder value a few weeks before a new CEO takes over after a second hedge fund said it had amassed a big stake in the coffee and doughnut chain. Tim Hortons shares jumped more than 4 percent on Tuesday after New York-based Scout Capital Management said it boosted its investment to 5.5 percent and met with management to discuss issues such as capital structure.

By Laurence Fletcher MONACO (Reuters) - The euro zone's debt crisis may be far from over, while Japan's money-printing gamble to revive its economy could destabilize global markets if it doesn't work, some hedge fund managers say. They are taking the view that the rally in financial markets over much of the past year, fuelled by central bank money printing, could mask a failure to tackle some European countries' and banks' debt problems, and the sell-off of recent weeks may be the start of a longer downward move.