The convention halls at the Aria Resort & Casino on the Las Vegas Strip were packed for four days this past week with bankers and their clients, in uniforms of Italian sportscoats and office sneakers. They fist bumped greetings as they strode to their next meetings, giving off the feel of a joyous reunion.

The hotel’s sky suites were booked. Citigroup bankers set up more than 900 meetings. A panel on data centers was so popular, attendees sat on the floor. Bank of America arrived with clients it had just taken on a ski trip to Park City, Utah.