Standard & Poor's downgraded the ratings on Marriott's long-term securities, saying the action reflects "the increased risk of Marriott's hotel development and resale business due to weakening lodging markets and an extremely difficult hotel financing environment."

Bally Manufacturing suspended dividend payments on common stock and said it will skip a scheduled interest payment of about $18.4 million on first mortgage notes of Bally Grand Inc., the subsidiary that operates Bally's Nevada casinos. Moody's Investors Service responded by downgrading the debt ratings of Bally and its subsidiaries.

United Airlines's management and two of its unions were called to Washington next week by the National Mediation Board as a step toward getting contract talks going again.

The FTC said it had no antitrust objection to the Carlyle Group's pending acquisition of BDM International.

Applied Vertical Systems, a Vienna computer software firm, was acquired by Welch Allyn Inc. Terms were not disclosed.

Financial News Network, the business-oriented cable TV service, said it has fired its chief financial officer for improper financial dealings.

Mortgage rates were mixed this week. Rates on 30-year fixed mortgages rose to 10.22 percent from 10.08 percent last week, while one-year adjustable-rate notes fell to 8.24 percent from 8.25 percent, the Federal Home Loan Mortgage Corp. said.

Northwest Airlines's largest union told the carrier that wage cuts are not an option in trying to solve a cash crunch created by soaring fuel costs. The machinist union said the firm has asked it to choose between laying off 10 percent to 20 percent of workers or taking a 10 percent pay cut for six months.

The National Institute of Standards and Technology is working to establish an industry-funded clearinghouse on destructive computer viruses.

Spa Lady Corp. auctioned off the 27 health spas in the Washington area to employee groups. Company officials said the health clubs will continue to operate under the Spa Lady name and will honor all membership contracts.

Miller Brewing said it would reopen its Trenton, Ohio, brewery in January, creating an undetermined number of jobs. Construction of the plant was completed in 1984, and it operated for a few months before closing.

Dow Jones & Co., publisher of the Wall Street Journal, is freezing budgets for capital spending and salaries and imposing other news and business cutbacks to cope with weak financial results and the sluggish economy. British Airways and the Soviet Ministry of Civil Aviation have joined forces to form a new airline called Air Russia to fly passengers from Moscow to Europe, North America and the Far East.