A tightly-spaced, 15-page document lands on the desks of senior General Motors managers every few days, updating them on special deals on dozens of the carmaker’s north American models.

Many of the promotions are targeted at carefully defined slivers of the car-buying public. GM is offering a $1,000 (€690, £514) cash discount in Chicago this week to coincide with the city’s annual auto show. US servicemen qualify for a special discount, and rebate certificates are regularly mailed to former customers who have deserted GM for rival brands.