When I neared my credit limit of $3000, I decided to pay down the balance to improve my credit score. I paid Citicorp $1875 within a three week period, bringing my balance down to $ 1125. Upon making a major purchase ( a computer) my card was declined.
I found that Citicorp had dropped my credit limit to $13oo immediately after receiving my big payment, despite the fact that I had not been late with a payment for over a year. Later I realized why they had done this: their balance sheet showed that I was still nearly maxed out. This became the rationale for raising my rates.
Thanks, Citicorp. Damned if I pay, damned if I don't.