ECONOMY

T-bill yields fell. The Treasury auctioned 13-week bills at an average discount of 7.12 percent, down from 7.20 percent last week and the lowest since 1988, and 26-week bills at an average of 7.13 percent, down from 7.16 percent and also the lowest since 1988. The investment rate was 7.35 percent on the 13-week bills and 7.50 percent on the 26-week bills.

The Treasury will hold its auction of $12 billion in two-year notes today. The auction had been postponed until the federal debt limit was raised.

COMPANIES

American Capital & Research of Fairfax and Acer Group of Britain formed a joint venture to market their engineering services worldwide. American Capital also announced that the Australian government has approved its acquisition of Kaiser Engineers Australia and Kaiser Engineers International. The terms were not disclosed.

National Gypsum and parent company Aancor Holdings filed voluntary petitions for protection under Chapter 11 of the federal bankruptcy code. The petitions did not include Austin Co., a Cleveland-based engineering services subsidiary.

Barclays Bank plans to streamline its British retail branch operations over the next five years by closing 110 offices and trimming 1,800 employees through attrition.

British Petroleum reportedly will announce plans today to dismantle its BP America Inc. headquarters in Cleveland, eventually moving or eliminating up to 900 jobs.

Kansas Gas and Electric agreed to a $1 billion merger with Kansas Power and Light. By becoming a subsidiary of Kansas Power and Light, KG&E would escape a hostile takeover attempt by Kansas City Power and Light.

Barnett Banks acquired the lease for the historic Biltmore Hotel in Coral Gables, Fla., for $24 million in a bankruptcy proceeding and said it would move quickly to reopen the shuttered hotel.

INTERNATIONAL

International air traffic is expected to increase by about 8 percent this year and more than 6 percent in each of the next four years, with the Far East experiencing the most growth, the International Air Transport Association predicted.

COURTS

A Utah jury ruled that a financial analyst's father is liable for insider trading in connection with a 1988 tender offer by American Stores for Lucky Stores. The SEC had accused the father of buying $15,000 in Lucky Stores options based on inside information from his son, who was an analyst for American Stores.

CONTRACTS

MCI Communications signed a three-year, $12.4 million contract with Midway Airlines to provide toll-free long-distance service for reservation centers and other operations.

EARNINGS

Boeing reported that third-quarter earnings increased more than 56 percent.

LTV reported a loss of $30.4 million for the third quarter of 1990, compared with earnings of $85.7 million in the same period last year.

R.H. Macy reported a loss of $215.3 million in the fiscal year ended July 28 compared with a loss of $53.7 million in the previous year.

ODD LOTS

American International Group said it will sue Public Citizen if the consumer group doesn't retract a claim that AIG could fail in a severe economic downturn. Public Citizen said it stood by its conclusions.