ECONOMY

Union membership in manufacturing registered a 3.2 percent drop in 1989, its biggest drop in three years, according to a forthcoming report by the Grant Thornton consulting firm. The decline was because of greater demand for high-tech workers.

The Resolution Funding Corp. auctioned $5 billion in 30-year bonds in strong bidding and at an average yield of 8.93 percent. Analysts called the bond reception impressive.

COMPANIES

Northrop will lay off about 1,400 workers at one of the Southern California plants building the B-2 stealth bomber. The cuts at Northrop's Pico Rivera facility are part of the company's plans to trim 3,000 jobs by the end of the year from its work force of 41,000.

General Electric scientists have grown gem-quality crystals with the ability to function as the world's best conductors of heat -- 850 percent better than copper, the company said. The company estimates that the market for the diamond crystals, which range up to one carat in weight, is between $50 million and $100 million a year.

Mack Trucks shareholders have filed a class-action lawsuit charging that Renault's $6 per share buyout offer for the truck maker is too low. The offering is scheduled to start Thursday and expire Aug. 8.

ACQUISITIONS

Washington Bancorp has finalized the sale of its mortgage subsidiary, Washington Mortgage Group, the company said. The purchaser, a group of Washington Mortgage Group management and private investors, is affiliated with the StoneLeigh Financial Group, an international financial services company. Terms of the transaction were not disclosed.

National Intergroup has filed a lawsuit against Centaur Partners, alleging that Centaur violated securities laws in connection with its ongoing proxy solicitation. Centaur holds a 16.5 percent stake in National Intergroup.

REGULATION

A congressional probe of tax compliance by U.S. subsidiaries of foreign-owed companies found that more than half of the 36 firms investigated have paid little or no federal income tax. The House Ways and Means oversight subcommittee's staff said that the IRS's international enforcement program suffers from a lack of coordination and resources and is simply "outgunned."

Western Union is being investigated by the Securities and Exchange Commission to determine whether Western Union filed false financial reports in connection with its recapitalization registration, the company said.

CONTRACTS

Martin Marietta received contracts valued at $24.7 million to build science instruments for two NASA space exploration missions. One instrument will study the composition of the dust and ice particles of the comet Kopff for 2 1/2 years. A second instrument is an imaging spectrometer that will produce x-ray images of quasars, clusters of galaxies and other celestial bodies.

EARNINGS

Dow Jones said its second-quarter earnings fell 28 percent from the same period a year ago.

ODD LOTS

Three commodities traders will be retried on charges of racketeering and fraud, said a prosecutor. A mistrial was declared after a jury returned verdicts on only 10 of 116 counts against Robert D. Mosky, Danny L. Scheck and David Zatz.