 Potentially U.S. homebuyers are finding slightly lower mortgage rates this week. The finance giant Freddie Mac says the borrowing costs on 30-year fixed rate mortgages ticked down to 6.89% this week. The average rate on the 15-year loan popular with those seeking to refinance has dropped to 6.17%. The Nasdaq is down 313 points at last check or 1.6%. It's NPR News.