Covered bonds have three potential advantages over MBSs as a method of mortgage finance.
First, they have the potential to reduce principal-agent problems, because the banks themselves
would hold the loans underlying covered bonds, giving them an interest in originating better
loans. Second, because the mortgage loans would simply remain on bank balance sheets and not
be put into special trusts subject to the incentives of servicers, banks could modify failing loans
far more easily than MBS trusts can. This could reduce foreclosures and maximize loan value.
Third, depending on how they are implemented, covered bonds also hold the possibility of
improving the options available to homebuyers who find themselves underwater. In Denmark,
covered bonds operate according to the “balance principle.” The balance principle requires a
match between each mortgage written and every bond issued. It permits homebuyers two options
for paying off their debt: they may either pay off their mortgage at par, or they may repurchase
their lender’s bonds on the open market, in an amount corresponding to the size of their
mortgage, and return those bonds to the lender. Falling house prices will often depress the
corresponding bond prices (though this may not always happen). When house and bond prices
fall together, homeowners can sometimes refinance their homes at the new, lower house price,
by buying back their bonds at the lower bond prices, and surrendering the bonds to the original
lender. This new option for refinancing could reduce foreclosures in the event of a widespread
decline in housing prices.
There is uncertainty, however, in the extent to which covered bonds would deliver the same level
of liquidity as GSE MBSs, because in a covered bond system, mortgage loans remain on bank
balance sheets. Moreover, it may be difficult for covered bonds to achieve the minimum efficient
scale to compete with government-backed GSE MBSs. As in Denmark, an effective covered
bond market would require standardized bond forms, and a high-volume market that could
demonstrate liquidity to potential buyers. If covered bonds were issued by hundreds of banks
across the country, each with different underwriting standards and bond structures, the extensive
market fragmentation would seriously reduce trading volume and liquidity for any particular
covered bond issue. The Danish covered bond system is effective because the market is highly
structured and homogenized, with only a few participating banks.
Me again: one of the selling points of covered bonds is that they remain on bank balance sheets, and, in Denmark anyway, have no explicit of implicit backing from the government. But do they really lack such backing? If the government is willing to inject liquidity into banks (and in Denmark, it is), do the bonds really lack a guarantee? I am not so sure.