The Aon company already has one skyscraper in the Windy City. 

SunTimes - In a $30 billion deal, Aon is buying Willis Towers Watson, a rival in business insurance and risk consulting, but it raises one question in the mind of most Chicagoans: What will happen to the Willis Tower name now that we’ve gotten used to calling it that?

Narrator's Voice: Chicagoans weren't used to calling it Willis.

If you asked 100 Chicagoans what the Willis company did, how many could tell you the right answer? 10? Maybe.

That's why I wonder just how valuable the naming rights to Chicago's tallest building actually is. Most still refer to it as the Sears Tower even though the name was officially changed to Willis in 2009.

But with the Willis name disappearing, that’s unlikely to continue. It’s possible that one of the tower’s marquee tenants, United Airlines Holdings, will bid for the naming rights.

People might get behind a United Tower just because of the familiarity of the company but I still think the majority would still call it Sears Tower.

No change is expected until 2025 when the Willis naming rights deal expires.