RE: Brent crude21 Apr 2020 11:03
Cardnal, typos fixed: "Negative trades throw a wee bit of cold water on commodity lognormal distribution pricing models!"
Simple concept: price of any commodity, or stock, can go to zero, or infinity upwards. So you are as likely to see a 50% decline as a 100% move upwards. This leads to a normal distribution of changes in prices, and makes all the math very easy to calculate how far we might expect a price to change in a day, week, or month in order to manage risk.
This is backed up by supply and demaind; if oil prices stayed near zero there would be unlimited demand, and people would buy GMC Suburbans with big block 454 7.4L V8s and drive a lot, very fast.
The real world unfortunately is much more complex than this, and so we sometimes see very huge moves, or more shockingly, negative prices during an epic delivery crash like yesterday in May WTI.
Excellent not too technical pricing distribution book to read is "The Black Swan" by Nassim Talib, very good read.