April 10 (Reuters) - BMW is considering adding

shifts to its Spartanburg plant in South Carolina to boost

output by up to 80,000 units, executives said on an analyst call

on Thursday, according to a note by Bernstein Research.

The premium carmaker had around 30 days' worth of inventory

in the United States as well as some stocks and components, and

would keep prices stable on most U.S. models until the end of

May, executives told analysts, according to the note.

The investor call was held before a closed period on company

information before annual results scheduled for May 7.