The most talked about and market moving research calls around Wall Street are now in one place. Here are today's research calls that investors need to know, as compiled by The Fly.Top Upgrade: Argus upgraded BHP Group (BHP) to Buy from Hold with a $68 price target. The firm says iron ore, copper, and coal prices, which drive BHP's results, are "firming as the global economy picks up." From a technical standpoint, BHP appears to be reversing a bearish pattern of lower highs and lower lows that dates to Marc ...