When a big exchange?
We are working on it, but with no result so far, some big exchanges refused us in the first place, some don't lists new coins at this moment and some didn't answered to our request.
We will keep trying, until we will bring to you a top exchange, unfortunately we can't tell when this will happen.
Also, users pressure is an important factor.
That pressure is better be driven toward the exchanges than the team.
The team does its best and submits listings, is willing to assist for integration, even specific dev if needed. But I guess an important factor in the decision process of the exchanges is "do our users really want that coin?".
There you can help, raise awareness of bismuth, tell the big exchanges (twitter, discord...) you want bismuth.