Ann: TVN SPP Offer Booklet and Letter to Eligible Shareholders, page-54

I would politely suggest you are showing a lack of understanding in etymology and semantics. You seem to be under the strange impression that 'banner month' means whatever you want it to mean. That's not how language works, unfortunately, Rdaneel.
Banner month means simply: 'a particularly good or successful period of time.' Now, this makes the appropriateness of its usage under any given circumstance inherently subjective. And so, you are welcome to hold your view as am I free to hold mine that delivering news at the close of the month that saw our SP spike 33% in the space of a day, our company's name broadcast loudly across leading publications, and a distinguished and decorated director welcomed to our board makes GW's usage of 'banner month' entirely appropriate. What you are not free to do, however, is give phrases your own personal definitions. And so I would invite you to 'think' a little more carefully next time yourself.