The Federal Housing Administration is in the red, according to an official audit released Friday, making a taxpayer bailout "all but certain." But the reality may be even worse.

The FHA's capital reserve was -1.44% of loan guarantees, or -$16.3 billion, according to a new independent audit. Last year reserves were still positive at 0.24% and $2.6 billion.

By law, the FHA — which insurers mortgages, mostly for low-income borrowers — is supposed to have a capital reserve of 2%.