I wanted to ask a question about the use of commas when separating two items in a list.
I was reading an article in Reuters concerning two different banks listed in the headline:
Deutsche bank, Rabobank hit with EU antitrust charge over bond cartel.
I tend to see this quite frequently in online press where two nouns e.g. two named banks are separated by only a comma. Often, this confuses me as I would assume the correct version of the headline would be one of:
Deutsche bank and Rabobank hit with EU antitrust charge over bond cartel.
or
Deutsche bank & Rabobank hit with EU antitrust charge over bond cartel.
However, I can't find any grammatical reason for why a comma is valid to separate just two items in a list. From my knowledge, we normally use a connecting punctuation such as an ampersand or a proposition e.g. 'and'.
Why do some articles use commas to separate just two items in a list?