Junipercards/Barclays recently lowered my credit limit from $1000 to $850. The primary reason - as they say - are my spending habits and account history. I always pay my bills on time, often 5-6 days before the due date, and alway more than the minimum. So account history is BULL**** AS far as spending habits is concerned: One big time speeding ticket. Wrote out one of those convenience checks. Use the card for online cigarettes purchases. And used card for 3 football games this past football season. Why TF would they care about my spending habits? Never went near the credit limit.
Indeed, they have to give some reason for adverse action, even if it is not triggered by anything you have done. They can't say "we're unable to securitize any more receivables therefore we're cutting back your credit limit".