The bank reported a 70-per cent plunge in annual net profits last year and said it would raise 12.5 billion pounds ($17.8 billion) in a record British rights issue.
HSBC, based in London, had been regarded as one of the more robust global banks as crisis devastated many top banks around the world, and has refused British government financial assistance.
"The world today faces exceptionally challenging economic circumstances," HSBC chief executive Michael Geoghegan said on Monday.
"2008 was a very difficult year for the financial sector, and 2009 will be no less so, as the global downturn intensifies."
The bank also said that its bad debts surged to almost $25 billion (20 billion euros) last year and that it would shut most of its HFC and Beneficial branches in the United States.
HSBC said net profits tumbled to $5.728 billion in 2008 compared to $19.133 billion in 2007 as the global financial crisis took its toll.
HSBC said it was slashing its annual dividend by 29 per cent to 64 US cents per share.
Its share price plunged 10.79 per cent to 438.75 pence in early London trading, mainly on news that the bank had to go cap-in-hand to raise fresh capital from shareholders.
"After talk of the need for raising cash was dismissed as recently as December last year this is a rather large slice of humble pie, and investors will wonder why such a supposedly well-capitalised bank is slashing the dividend and choosing to raise more cash of record-breaking proportions," said Martin Slaney, head of derivatives at GFT Global Markets in London.
"If nothing else this serves to underline just how severe the global economic contraction is."
HSBC said it would offer investors five new shares at a heavily-discounted 254 pence each for every 12 they already owned.
"In this difficult environment, we missed our profitability targets," HSBC chairman Stephen Green said in the group's earnings statement.
"The coming 12 months will be difficult. We expect parts of Asia, the Middle East and Latin America to continue to outperform Western economies, but to be constrained by the global downturn."
HSBC's difficult past year was largely a result of losses totalling 15.5 billion dollars at the group's American personal finance unit.
"The significant deterioration in US employment and economic outlook in the fourth quarter of 2008 were the primary factors in causing us to write off all the remaining goodwill carried on our balance sheet in respect of our Personal Financial Services business in North America," it said.
"It is now clear that models of direct personal lending that depend on wholesale markets for funding are no longer viable.
"In light of this, we have taken the difficult decision that, with the exception of credit cards, we will write no further consumer finance business through the HFC and Beneficial brands in the US and close the majority of the network," added HSBC.