home-security systems, increased its bond sale 60 percent to $1.2 billion as it raised funds to repay bank loans.

The acquisitive Bermuda-based company, which also owns medical devices, electronics parts and industrial valve businesses, sold $800 million of 30-year bonds at about 7.01 percent and $400 million of 10-year notes at 6.25 percent. The company expects "soon'' to broaden its funding sources by selling commercial paper, said J. Brad McGee, a company spokesman.

Tyco has announced more than $25 billion of acquisitions the past 20 months and is praised by many investors and analysts for keeping a rein on its borrowings and squeezing more profit out of the companies it buys. It limits purchases to companies that will immediately add to earnings and doesn't attempt hostile takeovers that could alienate company managers.

"This company is in markets that are growing eight or nine percent, and on their own are achieving ten to 12 percent internal sales growth before any acquisitions,'' said Brian Langenberg, a Chicago-based analyst for Credit Suisse First Boston Inc. "Your average conglomerate internal sales growth rate is maybe five percent.'' Tyco's earnings, before extraordinary items from acquisitions and early repayment of debt rose 64 percent in the year ended September 30 to $1.18 billion. That helped the company's stock rise 69 percent to 75 15/16 at Thursday's close, more than twice the 33 percent rise in the Standard & Poor's 500 Index.

With more than 40 operating businesses under its umbrella, now, Tyco remains committed to a strategy of growth by acquiring companies that fit within one of its four divisions, McGee said. "That doesn't necessarily mean they (investors) should assume the same acquisitions we've made in the last 18 months with respect to size.'' In November, Tyco agreed to buy AMP Inc., the largest maker of electrical connectors, for $11.3 billion of stock. Its bid topped a $9.8 billion offer from AlliedSignal Inc.

Tyco goes after companies that can fill gaps in its existing businesses.

Before last year's buy of US Surgical Corp., for example, Tyco catered to what it called the operating room's "periphery'' with disposable supplies like bandages.

US Surgical's products, such as devices to prop open blood vessels or examine internal organs, broadened the medical group's product offerings and helped open doors at big hospital chains. That helps it compete with industry giants such as Johnson & Johnson.

In the midst of its buying binge the past 20 months, Tyco has maintained its investment-grade ratings on senior debt of "Baa1'' by Moody's Investors Service and "A-'' by Standard & Poor's Corp.

"Their balance sheet is in excellent shape,'' said Young.