Ensuring a return offer in a BB regional/small IBD office

Most regional offices have their own retention policies, and tend to want to keep summer interns as much as possible (unless you're terrible). If you do a good job and fit in with the analyst team, you should be fine. In fact, it may even be easier than a head office like NYC - small teams often will take someone they find average immediately after a summer, rather than try to find someone better through FT recruiting. It's not a pretty risk/reward for them, and it's hard especially if culture is important.

In terms of advice - fitting in is more important for a return offer than the quality of work that you're putting out (which obviously has to be good as well). Go out with the analysts when they invite you (you have nothing better to do), ask higher-ups out to lunch when appropriate. Treat people with respect, maintain a positive attitude and a clean desk. You don't have to be extremely quick with your work, but you should try to make sure it's done right. Make sure you ask the right questions (it's okay to ask how to model deferred tax assets for a pharmaceuticals company, for example. It's not okay to ask how to paste special in Excel. You can Google that).