Lyft files to become a publicly traded company March 1, 2019, before Uber

$911 million loss?

Never mind that.  I am confused as to how Uber and Lyft could possibly be losing money.  They collect revenue off of the willingness of others to drive for them, and have relatively minimal expenses, at least seemingly.  I'm trying to imagine their expenses, which would include insurance, minimal overhead and advertising.  Perhaps the insurance expense for what they do is massive?

Prior to this I would have imagined the profits for these companies were through the roof.

https://www.cnn.com/2019/03/01/tech/lyft-ipo/index.html