Hmm.....never occurred to me to wonder about the maker of a photo frame....unless if course it said "Tiffany".
I looked on line and there don't seem to be many frame makers listed of that era.
Cute picture.
Linda C

I would say that it looks more like a monogram to me than a "maker's mark" -- either the person who bought the frame or the person who received the frame as a gift.

Thanks!

First off, you have a really choice frame.
This site has a similar example described as easel frame with gilded finish and SB monogram on the back.
Maybe you could send them your pic and ask for more info.
Keep us posted.

Here is a link that might be useful: Ruby Lane Frame

Could it be Shreve Crump and Low?

Here is a link that might be useful: Shreve Crump and Low

The frame pictured on Ruby Lane is hugely over priced....and over described.
Your frame is by the same maker, but very badly worn.
Frames like that date from about 1910 at the earliest.....and the price is very dependent on condition.