Investors who choose to join a campaign to seek bank repurchases of faulty mortgages from securities they own should steel themselves for a tough fight, even as the potential prize is vast, David Grais, an attorney advocate for asset-backed securities, said today.

Grais, addressing a crowd of more than 50 investors at the Core Club across the street from offices of bond fund giant BlackRock, outlined recourse that bondholders have if they were to enforce so-called representations and warranties on loans sold into subprime and other risky bonds made during the housing boom.

Some 45 percent of the mortgages in securities from 2005 to 2007 likely breached the assurances of loan attributes or quality, he asserted.

But the targets of the repurchases — including Bank of America Corp., the largest mortgage servicer in the country — are also girding themselves, he said.

"Any investor who chooses litigation ought to know in advance that opposition will be fierce, and one has to have fire in the belly in the beginning," he said.(Reuters)