We’re just about done with one of most hair-raising weeks in Wall Street history. Last night, Melissa and I joked darkly that if the House of Representatives fails to pass the credit-crisis rescue plan, something far, far worse than “black” Friday would emerge. More like: Void Friday, or Black Hole that Sucks Up Everything Friday. Fittingly, the Dow Jones Industrial Average nose-dived immediately after the Successful Vote to Prevent Financial Catastrophe.  Could be they suspect the cure will be worse than the disease — and they would know, because it’s their disease. 

The saying goes that the United States of America can be trusted to do the right thing only after all other options have been attempted. Given that the proposed bailout went from three pages and a $700 billion blank check to 400-plus pages of Congressional wish fulfillment, I’m guessing we’re still in “other options” territory. 

At a doctor’s appointment the other day, Melissa found herself explaining to the doc what the crisis is all about. The doctor said she talked to CEOs, economics professors and all sorts of educated types who were simply flummoxed on what the hell’s going on — this within a mile of Stanford University, Big Brain Central of the Bay Area. 

Melissa used to work in banking, where Doing Things Smart was carved into the industry’s granite columns and pounded into the heads of the little people who did all the grunt work. She has a hard time believing what happened, happened. People with no credit history granted mortgages on homes they could not afford. Financial wiz kids packaging these junk loans into A-graded “collateralized debt obligations” and selling them to greater fools the world over. Investment banks going under when their risky bets with borrowed money went south.

The keys to understanding what the hell’s going on are leverage and liquidity. I’ll start with leverage:

Everybody with a mortgage is already using leverage and not even realizing it: exploiting the advantages of investing with borrowed money. Say you want to buy a house that cost $200,000. Even if you had 200k lying around you wouldn’t want that much cash tied up in a single investment, so you’d take out a mortgage and put up only a small stake of your own cash: the down payment. If you put $20,000 down and sell the house later at a $20,000 profit, you’ve made a 100 percent profit on your 20k investment. If you put up your whole 200k and earn 20k, it’s only a 10 percent profit. You don’t need an MBA to see which is the smarter way to a) invest 20k and b) protect the other 180k from market risk.

Buying a 200k house on 20k is a 10-to-1 leverage ratio. Big-money investors have found that with clever computer models they can take on extravagant leverage ratios like 30-to-1 and enjoy extravagant profits by buying and selling intricate investment vehicles most commonly called derivatives. As long as they properly assessed the risks against their bets going south, they could rake in the cash. The great thing about massive leverage is how a small amount of your own money can reap a small fortune; the bad thing is that when you bet wrong, you lose money at a 30-to-1 clip and here’s the catch: even if you decide to sell to get out from under these bad bets, there are no buyers — this is where liquidity comes in.

Liquidity merely represents how easy it is to turn an asset into cash. You’ll never have any trouble cashing in your GE stock because millions of its shares trade every day. The big investment banks, meanwhile, had all these highly leveraged bets tied up in obscure financial assets with a very small pool of prospective buyers and sellers. When their bets on these assets started losing money, they couldn’t sell them even if they wanted to: there simply weren’t any buyers.

The federal rescue plan creates a buyer for these securities so financial firms can get them off their books. The securities — tied to home loans, bonds and other kinds of debt that have intrinsic value — can’t sell right now because the financial firms are in a panic spiral: they need free cash to stay alive, but selling off these assets at fire-sale prices obliges them to book huge losses that force them to put up even more cash.

The only way out of the panic spiral is to create a separate market for these securities. They’re worth plenty most of the time (bonds, loans and other stuff folks are highly motivated to pay off); right now everybody’s so focused on keeping the lights on that they can’t or won’t take on the risk. But there’s a decent chance that the feds can buy these securities cheap and sell at a tidy profit down the road.

So that’s a kinda/sorta explanation of what got us to this point. I’m hopeful because all previous predictions of the apocalypse have proved premature.