Usually, an automaker will announce they are ending production of a certain model. BMW didn't do that when it stopped production of the 6-Series coupe back in February.
Road & Track got confirmation about this change from a BMW spokesperson. No reason was given as to why production of the coupe ended, but it is a safe bet that low sales played a role in this decision.
This only adds fuel to the fire about reports that BMW is working on an 8-Series coupe. Our last report back in October said the company was planning to launch the 8-Series in late 2018 with the coupe. A convertible and V12 would follow sometime thereafter. Because of this, the 6-Series coupe and convertible would not be replaced.
Source: Road & Track