Here’s yet another ad from the 1921 Toronto city directory, since I enjoy them so much:
Here’s a close-up of the top of the building:
Did they really have a flag that read “Nerlich & C0.”?
There are lots of references to Nerlich & Co. on the Internet, since they used to manufacture postcards. They were around for a long time: there is a book commemorating the 50th anniversary of the company in 1908. They were at that location and producing catalogues as recently as 1955, but I have no idea what happened to them.
This site mentions that Nerlich & Co. moved to this location in 1901, but its writer doesn’t know what happened to them either. The Nerlich building still stands, though there appears to be nothing left of the lettering that used to be on the side of the building.