Former GM marketing boss Joel Ewanick on stage with Chevrolet Volt

According to reports from Adweek and The Wall Street Journal, General Motors is sticking with in-house ad agency, Commonwealth. This news comes despite the fact that GM recently informed Joel Ewanick, the brains behind the firm, that his services were no longer necessary. These reports further speculation that it was more than just a botched sponsorship deal with sports team Manchester United that led to the global marketing boss' demise.

Ewanick's other high-profile decisions at GM included dropping out of 2012 Super Bowl advertising and decimating the $10 million that was earmarked for Facebook advertising, a move announced just days before the social media site's IPO.

All of these actions played into the same cost-cutting strategy that brought about Commonwealth. Ewanick's brainchild, Commonwealth is only four months old. The Detroit-based Detroit-based ad agency is estimated to save GM $2 billion over the next five years.

The advertising house and the cost-cutting plans are still in place, but Ewanick is out. GM says that the executive "failed to meet expectations the company has set for its employees." He was given the option to resign, and at age 52 with stints at both Nissan and Hyundai under his belt, he stepped down from the chair of his very creation.

While General Motors looks for a replacement, Alan Batey, GM's U.S. sales and service vice president, will take over Ewanick's duties.