A charity that counts Nancy Reagan among its supporters is being investigated because of a report that it misled donors and sometimes gave less than half its donations to AIDS research, officials said.

"It seems that their expenses were enormously high for the amount of money they were giving to the organizations they promised," said Lanie Accles, a spokeswoman for state Attorney General Robert Abrams, who has subpoenaed the Creo Society's records.The investigation follows a Dec. 27 Better Business Bureau report, which found, based on the organization's records, that: "Of 13 events in 1987 and 1988, seven yielded less than 50 percent to charity," the bureau's minimum acceptable standard.

The bureau's New York Philanthropic Advisory Service, which investigated Creo for four months, said Creo had given it four sets of inconsistent financial statements.

Creo, founded in 1983, describes its mission as "raising funds for charitable purposes, notably for AIDS-related organizations."

In addition to Mrs. Reagan, supporters of the organization have included U.N. Secretary-General Javier Perez de Cuellar and King Juan Carlos of Spain.

The organization, whose name means "I create" in Latin and "I believe" in Spanish, has sponsored several lavish, high-society benefits, including a production of the musical "Hair" at the United Nations last May that was to raise $2 million for "children affected by AIDS."