Corporate credit quality fell sharply in the second quarter, Standard and Poor's said. It lowered ratings on about $190 billion of debt and raised ratings on about $34 billion. Downgrades outnumbered upgrades 4 to 1.

McDonnell Douglas stock moved higher on speculation about the company's future. The company denied financial market rumors that it planned to sell its Douglas Aircraft subsidiary to Japanese industrial giant Mitsubishi Group and that Chairman John F. McDonnell would resign.

Centaur Partners, headed by Melvyn J. Estrin of Bethesda, lost a Delaware court battle to force National Intergroup to expand its board to 15 members. Centaur will be allowed to try to elect only three members of the 10-member board at the July 25 shareholders meeting.

Mortgage rates were mixed this week. The interest rate on 30-year fixed mortgages rose to 10.11 percent from 10.06 percent and adjustable-rate mortgages fell to 8.45 percent from 8.46 percent, the Federal Home Loan Mortgage Corp. said.

Sears expects about a 32 percent drop in quarterly income per share from continuing operations because of losses in its insurance group and lagging earnings in the retail division. It did not give a bottom-line estimate.

Allegheny Ludlum and Quaker Chemical opted out of certain provisions of Pennsylvania's new anti-takeover law, which gives Pennsylvania companies 90 days to decide which, if any, of its provisions they want to adopt.

Drexel Burnham Lambert's bankruptcy case generated requests for more than $9 million in fees, covering three months of work, from lawyers and other professionals handling the case.

General Electric's Astro-Space Division will be paid $88 million to build and launch a broadcasting satellite for NHK, Japan's quasi-governmental television network. The satellite is to replace one lost in a launch failure earlier this year.

Asahi Breweries of Japan said it is looking for a suitable U.S. site to build a brewery to produce its Super Dry brand of beer. Asahi, planning a minimum investment of $667 million, dropped an earlier plan to build a plant in Denver in partnership with Adolph Coors.

Plea agreements reached in the fraud case against General Development, a Florida real estate developer, and two former officers who were charged with bilking customers of as much as $100 million were rejected by U.S. District Judge Lenore Nesbitt.

United Press International named Edgar Miller assistant managing editor for national news and Berl Schwartz Washington bureau chief. Washington news editor Arnold Sawislak, who joined UPI 41 years ago, will retire, the Washington-based news service said.