BOSTON -- Thermo Electron Corp. and Fisher Scientific International Inc. plan to announce a merger Monday to create a massive supplier of scientific and laboratory equipment, according to media reports.

The New York Times and The Wall Street Journal reported the planned merger Sunday night. The Times reported the deal valued at $11 billion; the Journal at $9.8 billion.

Spokesmen for the companies did not immediately return calls to The Associated Press.

The rivals, who have been buying smaller scientific instrument and chemical companies, would combine to become the nation's primary manufacturer and distributor of lab instruments.

The boards of both companies were expected to approve the merger Sunday night, and an announcement was expected Monday. The newspapers both cited anonymous sources.

Fisher Scientific, a 104-year-old company based in Hampton, reported net income of $389 million on revenue of $5.58 billion last year. Waltham-based Thermo, founded in 1956, reported net income last year of $223 million on revenue of $2.63 billion.

The deal, however, is structured as an acquisition of Fisher by Thermo.

Fisher shareholders would own about 60 percent of the combined company, which would be named Thermo Fisher Scientific Inc., The Times reported. Combined, there are 30,000 employees.

Thermo closed Friday at $39.45 on the New York Stock Exchange, and Fisher closed at $73.73.