SINGAPORE - Singapore Airlines, the world's largest airline by market value, posted on Thursday a 92 per cent slump in its fourth quarter net profit, dragged down by hedging losses and slowing demand.

Net profit tumbled by S$709.2 million, SIA said in a statement, as revenue fell 19.1 percent to S$4.84 billion.

Its full year net profit was S$1.06 billion, compared to S$2.05 billion in 2008 and analysts' forecasts of S$1.1 billion.

Singapore Air, which ranks ahead of Air China (601111.SS), said January-March net profit dropped to S$41.9 million ($28.6 million) from S$527.5 million a year ago, missing a forecast of S$176 million according to analysts polled by Reuters Estimates.

The carrier said "the decline in passenger and cargo carriage accelerated in the fourth quarter."

Singapore Airlines has seen falling passenger and cargo demand this year as the global economic slowdown hurt business and leisure travel, forcing it to cut flights from city-state to various destinations.

Singapore Air shares have dropped 11.2 percent in January-March period, underperforming a 3.5 per cent fall in the broader index .FTSTI.