HSBC Holdings PLC, Europe's largest bank by market value, reported Monday its steepest fall in profit since 2001 as costs for bad US mortgage loans mounted.

Profits for the first half of the year plunged 29 percent to $7.7 billion, compared to $10.9 billion in profits in the January to June period of last year.

"The first half of 2008 saw the most difficult financial markets for several decades, marked by significant declines in profitability throughout much of our industry," said HSBC Chairman Stephen Green. "HSBC was not immune from the turmoil."

The biggest losses came from the North American market, which HSBC depends on for a quarter of its revenues. The operations there posted a first-half loss of $2.9 billion, compared with profits of $2.4 billion a year ago.