regular expression – regex: how come the trademark symbol matches to a-z?

Sorry if this is a repeat or basic question but it is hard to search for a ™. I’m writing a script to remove weird characters from file names.

How come the trade mark symbol ™ matches [^a-z] ???

$ echo "AMD Ryzen™ 5 2600X Processor rstuv" |sed 's/[^A-Z]//g'
AMDRXP

$ echo "AMD Ryzen™ 5 2600X Processor rstuv" |sed 's/[^a-z]//g'
yzen™rocessorrstuv

$ echo "AMD Ryzen™ 5 2600X Processor rstuv" |sed 's/[^s-t]//g'
ssst

$ echo "AMD Ryzen™ 5 2600X Processor rstuv" |sed 's/[^t-u]//g'
™tu

™ seems to be between t and u ?