Nobody negotiates the US mechanical rate across a table. A tribunal sets it.
The mechanical royalty is the reproduction for : money owed to the writer and publisher whenever a of the composition is copied, downloaded or streamed. Every other music royalty has a price formed somewhere in a market. The mechanical, in the US, does not.
The reason is the statutory licence. Once a song has been commercially released, US law lets anyone record and distribute it without the writer's permission, provided they pay the and follow the formalities. A compulsory licence removes the right to say no, and with it the ability to negotiate a price. So the law has to supply the price instead. That job belongs to the Copyright Royalty Board (CRB), a panel of three administrative judges who set the mechanical rates in a litigated proceeding, then revisit them on a fixed cycle.
Who litigates? On one side, the publishers and songwriter organisations, arguing the rates up. On the other, the services, arguing them down. sit out the modern streaming fights for the most part: on streaming, are the services' bill, not the labels'. The proceedings run like trials, with discovery, expert economists and cross-examination, and the determinations can be appealed.
The UK works the other way round. There is no statutory mechanical rate here. Mechanicals flow through MCPS, the UK's mechanical , which negotiates licensing schemes with each class of user: record companies, broadcasters, online services. If a negotiation fails, either side can refer the scheme to the Copyright Tribunal, which has the power to set the terms itself. The backstop is rarely used, and that is the point: its existence disciplines every negotiation that settles short of it.
Same royalty, two machines. One is public, litigated and can change retroactively. The other is a private bargain with a referee on standby. An adviser with US-earning writers needs to understand both.