The chance for a brokered convention with so many 2020 Dem hopefuls is high. Would be an interesting market.
How much is known today about the vote distribution for the Democratic convention:
1. Will Democrats again have many super delegates?
2. Will Democrats distribute delegates proportionally in all states again or allow winner-takes-all distribution for later states?
If 1 is Yes, a first ballot decision becomes more likely, because the brokering can happen before the first ballot.
If 2 is Yes, a first ballot decision becomes less likely, because it is enough if three string candidates stay long in the race. Because Republicans had a No on 2, they avoided a drawn out ballot.