how are mortgage rates determined

how are mortgage rates determined: "Bad credit will really make bad image of your credit standing. Creditors and lenders are very wary about consumers with a problematic credit history. And it’s difficult for them to forget your record any time soon. It’s easy for them to access information regarding your credit standing. And you know that you might not always get the loan you need if your credit report comes out a little less than ideal. But the emphasis is on 'might not' because even with bad credit, it's still possible to obtain a mortgage refinance loan. The catch just simply rides on the refinance rate."