Credit Question

Is it normal for a bank to extend your credit limit without any kind of request? I wasn’t able to effectively Google that particular question. Anyway, Wells Fargo just upped my limit a little bit today with no notice whatsoever. I looked around and their site said they don’t extend additional credit until you’re a customer for a year. I’ve only been around 4 months. Oh well, it’s still less than Dell Premiere is willing to risk on me, though.