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

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

CEO Alan Mulally emphasized Ford’s namesake brand as he revived the US automaker. The timing of Mercury’s demise depends on how fast executives can convince the brand’s dealers to close or merge with Ford showrooms, they said.

Mercury would join Pontiac, Saturn, Oldsmobile and Plymouth among the departed Detroit brands of the 21st century.