I didn’t get it either. Turns out if you google ‘relationship between United Healthcare, Optum, and UMR’ – you’ll have the answer.
There’s a wikipedia article on the United Health Group. Apparently a ginormous company that would hate Medicare for all. Optum is a subsidiary that provides service such as pharmacy benefits.
UMR, I gather, processes claims.
Gee, one-stop shopping, and huge control over a segment of the market. What could go wrong?