[thaumasiotes]

Well, https://hsbc.banklocationmaps.com/en/chn/shanghai only lists one branch at a street address of 666, and that one is really just sharing the address of the commercial center where it's located, but that still seems like enough for this point.

8 is heavily represented. 6 is a runner-up. 7 doesn't appear to be significant in this context.

Consider the branch phone numbers:

3888 3888

3888 8468

3888 8900

3888 1200

6279 8582

3888 3111

3888 1318

3888 1188

3888 6455

3888 8618

3888 8688

3888 1218

3888 6388

There is technically one 7 in there, but it seems clear that the bank would have preferred not to have it. Counting only the second halves, 8 is overwhelmingly popular, so is 1 (for reasons I don't know), 6 is only barely ahead of what's typical, but still in third place, and 7 doesn't even exist.