Shares of home builders are faring notably worse than the broader market in the wake of S&P's downgrade of the US. Among the potential impacts that have been bandied about is higher borrowing costs for consumers. Increased mortgage rates are probably the last thing a market that is already suffering from a lack of buyers needs. Hovnanian Enterprises Inc. (HOV, $1.29, -$0.11, -7.86%), considered one of the sector's weakest players, is taking one of the biggest hits, while PulteGroup Inc. (PHM, $4.89, -$0.39, -7.39%) and Beazer Homes USA Inc. (BZH, $1.99, -$0.16, -7.44%) are also down.