The Financial Times said Europe's biggest bank was likely to unveil the plan to raise the sum, equivalent to 13.5 billion euros or $17 billion, with its full-year 2008 results on Monday.
But the paper said sources close to the plan warned that details such as the exact price of the offering were yet to be set and the proposals could still be postponed.
HSBC has fared better in the credit crunch than many of its rivals thanks to profitable operations in Europe and the Middle East and its history of maintaining a larger capital base than its counterparts.
But the sharply slowing global economy and the collapse of US bank Lehman Brothers has persuaded the bank to strengthen its capital ratios, the report said.
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