Stocks still have a long way to go before reaching a bottom, according to UBS. The bank on Monday said the S & P 500 will bottom in the second quarter of 2023 at about 3,200. That's 15% below where the index closed last week. "The lows are not in," UBS economist Arend Kapteyn said in a note to clients. He noted that the economy has yet to feel the "full effect of the rapid recalibration of monetary policy." The economist also said the U.S. will likely see an economic contraction in 2023 that will be on the "mild" end…