DETROIT (WKZO) -- The departure of two individuals from General Motors in the past week has investors nervous.

Global Chief Marketing Officer Joel Ewanick resigned Sunday and North American interior design leader David Lyon departed from the company Thursday.  Lyon left less than a week before he was to become GM Europe's vice president of design.

On top of the departures, GM's stock price fell to an all-time low last week since its November 2010 initial public offering.