Barclays Sallie Mae Auto Increase

My sixth statement just cut, and Barclays automatically increased my CL from $2000 to $5300. Had no idea Barclays did this and wasn't expecting it.

I've only used the card for gas and groceries, and have only gone over the cap for 5% cash back once or twice, so I doubt they're making much money off me. And, I've opened a half dozen cards since my account with "inquiry-sensitive" Barclays.