If they are handling the RD apps like last year, you may have a while to wait. Here is a message they sent out to RD applicants a few years ago on November 14:
"Thank you for your application to Columbia Business School. We will begin reviewing Regular Decision applications today, November 14, in the order in which they were received. Our goal is either to invite for an interview, or to deny an applicant, within six weeks from today. In practice, we expect to complete this process in less than four weeks. For updates on your status please login to your application status page."
I had clients that year who had submitted in Aug and Sept and got their final decisions in early Dec. Hope that helps. (Again, this is how it had been done in the past -- there is always a chance they could change things up, but since ED takes priority I doubt it will be too different this year.)
Beacon11 wrote:
What is the expected timing for interview invites / review of regular decision applications? I submitted RD in early September.