AIG, the world's largest insurer by market value, said yesterday its first-quarter operating profit had risen by a higher-than-expected 15 per cent, just ahead of Wall Street estimates. Excluding onetime items, it rose to $1.36 billion (€1.49 billion) from $1.18 billion in the same period last year. The New York-based company, with offices in the Republic, is the leading insurer of businesses in the US, but gets half its revenue from overseas, mostly in the Far East.