Industrial conglomerate Tyco International Ltd reported higher-than-expected quarterly earnings on Wednesday amid higher sales and margins in its security systems business.

The company, which also makes valves and fire safety equipment, posted net income of $400 million, or 85 cents per share, for the fourth quarter ended September 30, compared with $266 million, or 53 cents per share, a year earlier.

Earnings before special items were 92 cents a share, beating Wall Street estimates by 6 cents, according to Thomson Reuters I/B/E/S.

A lower share count helped boost earnings-per-share. The company spent $1.3 billion on stock buybacks during the year and has continued buying back shares since the end of the quarter.

Sales rose 4 percent to $4.69 billion, also above forecasts. Revenue was up 11 percent in Tyco's security business that includes ADT, its biggest segment, but operating profit jumped 30 percent, helped in part by improved demand from commercial customers.

This was the first earnings report since Tyco announced plans in September to split into three companies, potentially turning its businesses into acquisition targets.

Tyco said the split would allow its three businesses -- ADT North America residential security, flow control products and services, and a fire and security business -- to have more options for growth. That split is on track to be completed this fiscal year, it said.

Tyco said it would give a fiscal 2012 forecast on its conference call before the start of trading.

(Reporting by Nick Zieminski in New York; Editing by Lisa Von Ahn and Derek Caney)