Mountune was recently rescued by the original founder (don't laugh, a guy named Mountain) and a group of investors. Lost money last year and was on the market. They hope to revive the company and get into electric car parts. The USA has never been a big market compared to the EU. I hate it but the US market has died for them and I'm sure Ford Performance will continue to sell the US unique ST parts if they do bail out from Cali or convert to a warehouse/drop ship for Ford Performance. When investors buy a company losing money cuts are inevitable. Lots of complaints about what used to be their strong point, Customer Service on the Forum and stocking issues. So decreased staff is probably the reason for poor customer service and lack of money in the stocking issues. Their parts still viable in the US market like radiators, exhaust, hoses and engine parts are already sold by Ford Performance and tunes are dead for them in the USA. Until we dump Trucks, SUV's and CUV's there is no market for hot hatches with tiny powerful engines. A partial quote from the article; " We can’t wait to get back to supplying and supporting our customers and dealers properly ......."
https://www.autocar.co.uk/car-news/industry/tuner-mountune-goes-independent-acquisition-founder
https://www.autocar.co.uk/car-news/industry/tuner-mountune-goes-independent-acquisition-founder