Oil prices went negative a year ago: Here’s what traders have learned since WTI https://www.marketwatch.com/story/oil-prices-went-negative-a-year-ago-heres-what-traders-have-learned-since-11618863839#:~:text=On%20April%2020%2C%202020%2C%20the,the%20New%20York%20Mercantile%20Exchange.