From the “history doesn’t repeat, but it rhymes” department, an extract from the excellent PBS series on the Great Depression, courtesy of Jesse’s Café Américain:

NARRATOR: Everything was not fine in 1929 with the American economy. It was showing ominous signs of trouble. Steel production was declining. The construction industry was sluggish. Car sales dropped. Customers were getting harder to find. And because of easy credit, many people were deeply in debt. Large sections of the population were poor and getting poorer.

Just as Wall Street had reflected a steady growth in the economy throughout most of the 20s, it would seem that now the market should reflect the economic slowdown. Instead, it soared to record heights. Stock prices no longer had anything to do with company profits, the economy or anything else. The speculative boom had acquired a momentum of its own.

NARRATOR: Wealthy investors would pool their money in a secret agreement to buy a stock, inflate its price and then sell it to an unsuspecting public…

Mr. ROBERT SOBEL (Historian): I would say that practically all the financial journals were on the take. This includes reporters for The Wall Street Journal, The New York Times, The Herald-Tribune, you name it. So if you were a pool operator, you’d call your friend at The Times and say, “Look, Charlie, there’s an envelope waiting for you here and we think that perhaps you should write something nice about RCA.” And Charlie would write something nice about RCA.
A publicity man called A. Newton Plummer had cancelled checks from practically every major journalist in New York City.

Mr. NESBITT: Then, they would begin to — what was called “painting the tape” and they would make the stock look exciting. They would trade among themselves and you’d see these big prints on RCA and people will say, “Oh, it looks as though that stock is being accumulated.”

Mr. SOBEL: Now, if they are behind it, you want to join them, so you go out and you buy stock also. Now, what’s happening is the stock goes from 10 to 15 to 20 and now, it’s at 20 and you start buying, other people start buying at 30, 40. The original group, the pool, they’ve stopped buying. They’re selling you the stock. It’s now 50 and they’re out of it. And what happens, of course, is the stock collapses.” [and on a large enough scale, the stock market, and the regional or national economy].