If underwater borrowers follow Jim Cramer’s advice to "walk away", it looks like we’d see an exodus of biblical proportions:

NEW YORK (Reuters) – One-tenth of U.S. homeowners hold mortgages that are larger than the worth of their homes, Moody’s Economy.com said on Friday.

Nearly 8.8 million homeowners, or 10.3 percent, are in over their heads, its chief economist, Mark Zandi, estimates.

As a result, millions of U.S. homeowners have the incentive to abandon their properties.

Thinking of moving?  Sounds like you’d better reserve the U-haul now.