ALCAN UPS ALUMINIUM INGOT AND BILLET PRICES Alcan Aluminium Ltd. in Montreal said it increased yesterday its prices for unalloyed ingot and extrusion billet by two cents a lb, effective with shipments beginning May 1. The new price for unalloyed ingot is 64.5 cents a lb while the new price for extrusion billet is 72.5 cents a lb. "We feel very confident about raising our prices because we see demand over supply as being sustainable for some time," said Ian Rugeroni, Alcan's president of metal sales and recycling - U.S.A. Rugeroni said sheet and can bookings for Alcan aluminium were up at a time when the company's total 1.1 mln tonne North American smelter system had less than a week's supply. "We're short and we're buying," he said. Rugeroni added that Alcan expects the International Primary Aluminum Institute to report a drop in total non-Socialist stocks in February and March. He estimated supply in the latter month will have fallen 100,000 to 150,000 tonnes, based in part on current low inventories of aluminium in Japan and on the London Metal Exchange.