The filings with the Securities and Exchange Commission were made by Toks Inc., which describes itself as "a development stage company that will engage in diversified operations like production of entertainment and media contents."
"It's not a valid filing," said an AT&T spokeswoman, who denied any such deal.
An SEC spokesman said the agency is checking out the filings, which propose a combination that will make Toks the parent of AOL Time Warner Inc., AT&T, AT&T Wireless Services Inc., GE, GM, Hughes Electronics Corp. and Marriott International Inc.
"Synergies could create up to additional over $300 billion in annual revenues, even after liquidation of assets or spinoffs recommended by regulators," the filings said. "This is just an initial proposal," it added.
A GM spokesman said the filings marked the first time the carmaker had heard of the proposal. "We're as mystified about this as you are," he told Reuters.
A Sept. 7 stock registration filing by Toks, for 20 shares at $5,000 each, lists a Los Angeles, Calif., phone number. A message left for comment was not immediately returned.
An expert with SEC filings speculated that someone gained access to a password for the SEC's huge database known as EDGAR, or Electronic Data Gathering Analysis and Retrieval, and submitted the filing.
The expert, who did want to be identified, said the filing might not even be reviewed because was so ridiculous, although the SEC's crime-fighting enforcement division might want to probe for possible fraud if the person who made the filings held stock in one of the companies.
"If he claimed he was going to take over Marriott and he had some Marriott stock, well, then, that would be a different story," the filings expert said.
A scan of SEC stockholder filings does not show Toks to be a major investor in any of the seven companies it plans to "acquire."
The SEC could seek a stop order, preventing someone from going forward with a proposal, if the commission thinks a document is a fraud, securities lawyers said.