NEW YORK (Bloomberg) — Bermuda-based Tyco International Ltd., the world's largest maker of security systems through its ADT unit, posted first-quarter profit that exceeded analysts' estimates and spurred the biggest share gain in more than six years.

Profit from continuing operations declined 24 percent to $272 million, or 57 cents a share, from $360 million, or 72 cents, a year earlier, the company said today in a statement. Revenue in the quarter ended December 26 fell 8.5 percent to $4.43 billion.

The company said it December it is seeking to move its headquarters from Bermuda to Switzerland, which has an established tax treaty with the US.

Total sales in the quarter reached the high end of the company's own forecast, while trimming expenses helped improve profitability. Tyco raised its estimate for cost-cutting charges this year to as much as $150 million from $50 million as the company shrinks to cope with the slowing economy, chief executive officer Ed Breen said on a conference call with analysts.

Better-than-expected results "were driven by substantially better operating margins", Nigel Coe, an analyst at Deutsche Bank, wrote in a note to clients. "With growth in the recurring revenue and modest backlog build, this result will likely be viewed in a favourable light." He has a "buy" rating on Tyco.

Tyco rose $2.95, or 15 percent, to $23.29 at 10:02 a.m. in New York Stock Exchange composite trading. Earlier, the shares jumped 18 percent, the biggest intraday percentage increase since July 26, 2002.

In the quarter, results fell in each of Tyco's five main divisions, hurt by the strengthening US dollar and weak demand in North America and Europe. Excluding some items, Tyco International earned 61 cents a share. The average of 12 analysts' estimates compiled by Bloomberg was for 47 cents.

For the year ending in September, per-share profit will be $2.28 to $2.50 a share, excluding potential restructuring costs of eight cents a share, Tyco International said. That's in line with the previous November forecast that included such costs and was $2.20 to $2.50.

Tyco International decided to exclude the restructuring costs because they aren't yet set and to make the forecast "as neat and clean as possible", Breen said. As economic conditions become more clear, Tyco will update the forecast on cost cutting, he said. The unchanged $2.50-a-share end of the range reflects a reduced outlook for the electrical and metal unit.

Tyco International, run from West Windsor, New Jersey, projected on November 11 that first quarter profit from continuing operations excluding some items would be 46 cents to 49 cents a share.