[zeroCalories]

They could be engaging in a form of market making, where they buy tickets that are near certain to be sold so that sellers feel good about listing on their site. I don't know about their customers' behavior, but I imagine many buyers buy at the last moment, and sellers feel anxious wondering if they will be able to sell, making them look for other platforms.

[lq9AJ8yrfs]

This. Plus different sellers have different motivations and different pricing strategies. Stubhub based on their volume has a sense of where the market is, and if they see a seller underpricing versus what Stubhub thinks the ticket will sell for, they may swoop in and try to capture some of the upside.

There's no such thing as a ticker feed for the resale markets -- the market is characterized by "imperfect information". Artists and venues making it hard to buy and sell basically widens the spread for the secondaries to play with.

[hotpotamus]

I never thought about it, but I suppose a concert ticket is similar to a futures contract. I'm sure some fintech whiz-kids figured that out years ago and have been at work figuring out how to make money on yet another market.