Stock market live Monday: Dow tanks 500 points, rough September, Nikola plunges 19%

This is CNBC's markets live blog that will be updated throughout the day. 

Wall Street's September sell-off intensified on Monday amid worries about the worsening pandemic. The declines added to the major averages' three straight losing weeks. Bank stocks came under pressure after a report found global banks moved allegedly illicit funds. Once red-hot Nikola plunged with founder Trevor Milton voluntarily stepping down. Technology stocks had a late day comeback. Here's what's happened.