NEW YORK - August 10, 2011 - Standard & Poor’s lowered the AAA ratings of thousands of municipal bonds tied to the federal government, including housing securities and debt backed by leases, following its August 5 downgrade of the U.S., reports Bloomberg.

The rating company assigned AA+ scores to securities in the $2.9 trillion municipal bond market, including school construction bonds in Irving, Texas; debt backed by a federal lease in Miami; and a bond series for multifamily housing in Oceanside, Kalifornia.

S&P spokesman Olayinka Fadahunsi said he couldn’t provide a dollar figure on the affected debt.

Be very careful holding muni-bonds. A downgrade of a muni debt can be very costly in terms of interest rates for some of these municipalities - some of them, on their own, already are substandard credit risks.