B.S.O sterling silver vessel

[AllSeasons]

I recently acquired this piece (probably a sugar bowl), but I have never heard of the maker. It's marked "B.S.O" or "B.S.C", along with "STERLING" and "90". I couldn't find this mark anywhere online. Based on the way it's marked, I assume it's American made, but could be wrong. The closest I could find to BSC is Birmingham Silver Company in the US, but they make mostly silver on copper items, and their mark looks markedly different. The closest I could find to "B.S.O" is Bjorn Sigurd Ostern, which would make this piece Danish. Any insight would be greatly appreciated.

Images are below. Thank you in advance!

[dragonflywink]

Barbour Silver Co.

~Cheryl

[AllSeasons]

Barbour Silver Co.

~Cheryl

Great, thank you!