ECONOMY

T-bill yields fell. The Treasury auctioned 13-week bills at an average discount of 7.02 percent, down from 7.08 percent last week, and 26-week bills at an average of 6.96 percent, down from 7.05 percent. The investment rate was 7.24 percent on the 13-week bills and 7.31 percent on 26-week bills.

Virginia exports are likely to exceed $9 billion this year, up from $8 billion last year, according to Alliance International, a Norfolk trade management company.

Working oil and gas rigs rebounded by 72 this week, following two weeks of declines, to bring the total to 1,175 nationwide, toolmaker Baker Hughes reported.

COMPANIES

The Big Three automakers announced temporary layoffs of 12,600 employees in Canada in addition to the 38,800 U.S. employees being furloughed due to sagging North American sales.

Automotive Industries in Strasburg, Va., furloughed 200 of its 970 employees for one week because of the economic slowdown and automobile production cutbacks. The firm makes molded plastic interior parts for the Big Three automakers.

Midway Airlines agreed to delay completing its sale of airline gates and other assets at the Philadelphia airport to USAir until after Saturday, and possibly later, to allow the U.S. Justice Department to complete its review of the proposed transaction. Meanwhile, Midway's pilots union has approved a new, three-year contract with the airline. Terms of the pact were not revealed.

AT&T and Microwave Corp. entered into an agreement to develop advanced microwave radio products for use in phone networks and private radio systems.

Navistar said it more than tripled its stake in Mexico's largest truck builder, DINA Camiones, to 17 percent and agreed to supply DINA with as many as 5,000 diesel engines annually.

Braniff and its unsecured creditors have filed a complaint against its former management and an adviser, accusing them of illegally draining cash from the financially ailing airline. The complaint filed in federal bankruptcy court earlier this month seeks $18.5 million in compensatory and punitive damages.

Whittle Communications said more than 5,700 schools have signed contracts for its commercially sponsored Channel One news show for teens, and expects to reach its goal of 8,600 schools by next June.

BHA Aviation said it withdrew its cash offer to buy Eastern Express, the regional carrier operated by bankrupt Eastern Air Lines, after failing to reach agreement on certain provisions of the proposed deal.

A&M Records said it would distribute pop artist Sting's upcoming release in a more environmentally sound package than the standard "longbox" used for most compact discs.

Hughes Aircraft said it has set up a company in Spain to supply the expanding commercial and industrial markets for electric components in Europe.

ACQUISITIONS

J. Fernando Barrueta and principals of Barrueta & Associates acquired the outstanding minority interest of the Washington-based commercial real estate firm on Nov. 21 from an affiliate of developer Conrad Cafritz, who is selling assets in an effort to avoid bankruptcy. Terms were not disclosed.

REGULATION

The Justice Department said it collected $257 million in fiscal 1990 from defense contractors and other companies accused in civil suits of defrauding the government. The amount has risen substantially since 1986 when Congress authorized the government to recover triple damages.

INTERNATIONAL

Iran agreed to buy heating oil and kerosene from refineries in Bahrain, Qatar and Abu Dhabi. In the past, many Persian Gulf nations that supported Iraq in its 1980-88 war with Iran had banned the sale of oil products to Iran. But Iraq's invasion of Kuwait has reversed that situation, and the Arab states are now actively courting Iran.

PEOPLE

LTV said that Richard J. Boyle, a Honeywell vice president and veteran of 25 years in the aerospace and defense business, has been appointed president and chief executive of its LTV Aerospace and Defense Co.

Hills Departments Stores said Thomas H. Lee, a director and Hills's largest stockholder, has been elected chairman and chief executive, succeeding Stephen A. Goldberger, who resigned.

ODD LOTS

Cargill, a Minneapolis commodities marketer, again ranked No. 1 on Forbes magazine's list of private U.S. firms with the largest sales, having revenue of $44 billion last year. Koch Industries, a Wichita petroleum, natural gas and chemicals firm, was second with $17.2 billion in sales. Mars Inc. of McLean was ranked seventh, with estimated revenue of $7.5 billion.

Miglin-Beiter is expanding its search for financing for what it hopes will become the world's tallest building. The firm, which hopes to break ground in Chicago on the 125-story structure by spring, said its new funding push will focus on Dutch and Japanese pension funds.