Nearly 40,000 Robinhood day traders added Tesla shares in 4 hours Monday as the stock whipsawed (TSLA)

· *Nearly 40,000 Robinhood accounts added shares of Tesla during a four-hour period on Monday, Bloomberg reported, citing data from Robintrack.net. *
· *The automaker's stock went on a wild ride Monday, gaining as much as 16% at one point before falling and closing down 3%. *
· *Now, Tesla is the 10th most popular stock on...