Ford Motor Co. is preparing to wind down the Mercury line, created in 1939 by Edsel Ford, after sales plunged 74 percent since 2000, two people familiar with the plan told Bloomberg News.

The automaker’s top executives are preparing a proposal to kill Mercury to be presented to directors in July, said the people, who asked not to be indentified revealing internal discussions. Mercury, losing two of four models next year, will be starved of products and promotion, the people said.

CEO Alan Mulally emphasized the automaker’s namesake brand as he revived the only major U.S. automaker to avoid bankruptcy. The timing of Mercury’s demise depends on how fast executives can convince the brand’s dealers, who also sell Lincoln models, to close or merge with Ford showrooms, they said.

Mulally also is unloading Ford’s European luxury brands, after the automaker failed to achieve a goal to have them generate one-third of automotive profits. Ford in March agreed to sell Volvo to China’s Zhejiang Geely Holding Co. It sold off Jaguar, Land Rover and Aston Martin in the last three years.

“We continue to evaluate all of our models and brands,” Mulally told reporters in Washington, D.C., yesterday. “We have no change in our position about Ford or Lincoln or Mercury.”

Mercury would join Pontiac, Saturn, Oldsmobile and Plymouth among the departed Detroit brands of the 21st century. Sales will end within four years, one of the people estimated. General Motors Co., as part of its U.S.-backed reorganization last year, sold or closed four of its eight brands sold domestically.