Ally Financial Inc (NYSE:ALLY) is up 3% in trading today, but with so many different news items it’s hard to say for sure which one is driving the price up. Arguably the most important long-term change is that the US Treasury announced that it would sell an additional 75.1 million shares of Ally on the open market, significantly reducing its stake and removing a major overhang that has kept investors away despite strong quarterly performance. Treasury sale of Ally Financial stock is a significant net positive: BTIG “While the U.S. Treasury’s sale of ALLY translates into increased supply of stock…