As stated in this article, Best Foods' and Hellmann's mayonnaise are the same product (and company ownership). The article also says that Best Foods' mayonnaise is available on the west coast and Hellmann's mayonnaise is available in the east, and that the only place both brands are available is in Denver (area).
I live in Lakewood, a suburb of Denver. I can't attest to the brands not both being available outside the Denver area, but I can attest to both being available in the Denver area, side-by-side on the shelf. I long ago realized that the labels on the jars were identical except for the name, when someone advised me to only buy one brand, not the other.
According to the article (I'll have to check the labels), Hellmann's has less sodium than Best Foods.
Why do they call it Bank of American then?!?!
Claudia, my mother, who had lived in LA since the 20s told me that, until WWII, it was called "Bank of Italy" (although I doubt that it had a branch in Rome, either). When WWII started, they changed the name from Bank of Italy to Bank of American to avoid anti-Italian sentiment.