They are also higher in such fields as muni bonds backed by hospitals.

He called for new investment in the country's 379 national parks, including the creation of bonds backed by park visitation fees.

Other groups expressing concern about the case include financial institutions seeking to sell bonds backed by Florida's settlement funds, those people said.

Mexican officials said that in the next week or so, they will offer longer-term bonds, backed by the new American credits.

During his tenure, the fund has kept 60 to 75 percent of its assets in bonds backed by Government agency mortgages.

At least 20 states have issued bonds backed by their share of the $246 billion, 25-year settlement reached with tobacco companies in 1998.

Indeed, bonds backed by mortgages are particularly susceptible to early redemption.

And it has also been a popular time to invest in mutual funds that buy bonds backed by home mortgages.

But times quickly changed, and at the end of 1996, there was an explosion in the demand for call-protected bonds backed by commercial real estate.

They are mainly bonds backed by mortgages on mobile homes, also known as manufactured housing.