Masco Corp., maker of some of the best-known products in the home-improvement and home-construction business, is suddenly in favor on Wall Street. The reason: speculation that the company will spin off or sell some of its top brands.

Masco is one of the largest vendors to Home Depot Inc. and Lowe's Cos ., which sell hundreds of the company's products including Delta faucets, KraftMaid cabinets, Behr paints and Milgard windows and doors. The company also sells to home builders and installs its products in homes under construction.

But at an investor conference last month, Masco's new chief executive, Keith Allman, hinted that the company might have too many brands and divisions. He said he is reviewing Masco's multiple business lines and considering strategies to boost Masco's value.

The comments set off a rally that boosted Masco's common stock 11.5% in the past month, before a slight pullback in the past week. It closed Tuesday at $21.72, down 0.3% on the New York Stock Exchange but still near its 52-week high of $23.63 set in March.

In an interview this week, Mr. Allman said he hasn't yet made any major decisions about Masco's many businesses but indicated that big changes are ahead for the 85-year-old company.