GM earnings beat estimates on strength in North America

By Bernie Woodall and Joseph White DETROIT (Reuters) - General Motors Co on Thursday reported higher-than-expected quarterly earnings, citing strong results in North America and an improved performance in Europe. The automaker's shares were up 2.8 percent at $33.10 in early trading, about flat with their 2010 initial public offering price of $33 despite three straight quarters of record-breaking pretax profits. Chief Executive Officer Mary Barra has stepped up efforts to persuade skeptical inves