Markets ended a rollercoaster week on an upbeat note, giving the S&P 500 its biggest weekly gain in nearly two years and erasing December losses.  Markets were pulled in different directions by several factors, including central bank actions, a deep slide in the Russian ruble, and further gyrations in oil markets.  For the week, the S&P 500 gained 3.41%, the Dow grew 3.03%, and the Nasdaq added 2.40%.

Click here to read the full article.