As much as $800 million worth of the mortgage-backed issues were rumored to have been sold.

Yields on the mortgage-backed issues ranged from about 1.25 percentage points to 1.55 percentage points more than Treasury issues of similar maturity.

One example is the Blackrock Investment Quality Trust, which owns Government securities, mortgage-backed issues and corporate bonds that are rated A, not much above the junk level.

Deregulation has allowed commercial banks to underwrite selective asset-backed, mortgage-backed and municipal issues.

His portion of the fund is divided among corporate bonds (40 percent) and mortgage-backed and government issues (30 percent each).

All fixed-income securities, whether convertibles, high-yield bonds, AAA-rated corporates or mortgage-backed issues, are traditionally evaluated by how much more their coupons yield than Treasury securities with similar maturities.

On Friday, at least $325 million of new corporates were offered, as well as $860 million of new mortgage-backed issues.

Each mortgage-backed issue represents thousands of home loans around the country.

The steepest price declines came in the afternoon as securities dealers sold Treasury issues to protect themselves against losses on mortgage-backed issues they had bought or were committed to buy.

For investors who want to sell their high-yield bonds, emerging-market debt, convertible securities, even some mortgage-backed issues, there is still no place to go.