American Motors Corp. shareholders voted virtually unanimously today to accept an expansion of French automaker Renault's ownership of the company to between 46.4 percent and 49.9 percent of outstanding shares.

AMC Chairman Gerald Meyers said that only "1, or 1 1/2 percent" of the smallest U.S. car maker's shares were voted against giving the French company approximately half of the U.S. firm. They had little choice, being told earlier the only alternative would be bankruptcy.

Meyers told a news conference after the 49-minute meeting that if Renault exercised all its outstanding warrants, options and the like, that share could rise to 59 percent. Neither AMC nor Renault expects that to happen, Meyers insisted.

Renault is owned 92 percent by the French government and 8 percent by its employes, Bernard Vernier-Palliez, chief executive officer of the French automaker, told the roughly 200 AMC shareholders at the meeting.

Despite that, the company has been run "exactly like" a private, profit-making company, Vernier-Palliez said.

Meyers termed the agreement "our formula for the future," predicting there will be no more than 12 or 15 automakers worldwide by the year 2000. "To survive into the '80s and '90s, we need to be a world-class company," he said.