In the past when I had people in their IEP who didn't want coverage to start till the next month (let's say T65 December ) has employer plan through end of year, we would tell them to apply in early December to avoid an extra month of B. This month I have started seeing people get their B backdated to 12/1 even when they applied in December. So we looked into it, and apparently now SSA bases it off of when you start the application, not when you submit it. That is what ssa told a client, they said since she started it in November, but submitted it 12/8, it would be retroactive to 12/1 even for Part B. Ok, that was news to me. So then I had another lady who started and submitted her application on 12/1. Hers was also backdated to 12/1. Any clue why this is? If she had started the application on 12/2 would this have also happened?