Hi there!
There are hundreds of thousands of marks which are just initials on contemporary jewelry (Is that 925 preceding the initials?)
Chasing down a mark on contemporary jewelry can be very time consuming and even if you do ID the maker/company that doesn't guarantee that it will be more desirable from a selling point of view.
Believe me I have done this myself because I always fear that have a "sleeper" and will undersell something. But generally speaking if the item is mass produced and contemporary my 10 cents would be don't spend a lot of time on research.
If folks here don't know what that mark is chances are it isn't a well known designer and you can simply sell the item stating it has a mark.
Hope someone here can ID that for you, but if not, don't sweat it! 
