While Carolin's answer is certainly not wrong, I am a bit puuzled as to why Brigitte did not mention one of the comments made at the other question (but I very much appreciate you linking the old query, Brigitte):
"Terry Moran: Definitely US English rather than UK, but I don't have an alternative suggestion"
A) I think he's right and B) I do have an alternative term: "trail commission"
Please see:
https://www.fca.org.uk/consumers/trail-commissionhttp://www.telegraph.co.uk/finance/personalfinance/money-sav...https://en.wikipedia.org/wiki/Trail_commissionLEO, dict.cc & other databases (i.e., websites that pretend to be dictionaries, but where there is no real oversight) typically give little indication as to the EN variant in which a word is used and I believe Jo needs it in BrE.
However, Jo, please be aware (not sure whether you need it):
"They have already been banned in other jurisdictions, most notably the United Kingdom and Australia."
http://www.cbc.ca/news/business/mutual-fund-trailer-fees-1.3...[Yes, CAN calls it "trailer fees" again, much like its southern neighbor]