The credit market remains exceptionally tight these days. In spite of (or perhaps because of) Uncle Sam's help, almost no company that actually needs a loan is able to get one from a private lender at decent rates.

In fact, those that can get money at all are forced to pay outrageous interest for the privilege. General Electric , for instance, is paying Berkshire Hathaway 10% on its preferred shares, and GE had to sweeten the pot with warrants to get its rate that low.

And GE is a profitable industrial titan -- once the world's largest company -- that even after its recent downgrade still sports an impressive AA+ debt rating. When a company like that needs to dilute its shares to get money loaned to it at double-digit rates, you know the credit market is tight.

Although it's difficult and expensive, GE can borrow the cash it needs to operate. But not everyone is so lucky.

Who's at the biggest risk?
In a credit environment this tight, companies that can't either roll over their debt, or pay their debt and operate with what they have, are in danger of going under.

But with the possible exception of law firms that handle bankruptcies, nearly every company is feeling the pain of this economic downturn. So how can you tell if a company is struggling just like everyone else -- or about to fail?

These three signs should make you sit up and take notice:

When you put all three of those high-risk signs together, you get companies like these:

Company

Tangible Book Value

TTM Net Income

Total Debt

Boston Scientific (NYSE: BSX)

($6,263)

($2,371)

$6,247

Genworth (NYSE: GNW)

($981)

($572)

$9,585

Sara Lee (NYSE: SLE)

($617)

($248)

$2,812

Cablevision (NYSE: CVC)

($8,753)

($228)

$11,990

Delta Air Lines (NYSE: DAL)

($14,128) Continued...