2008's economy can be divided into two parts. The first is the period between January and July when oil prices ran up to $147 thanks to a speculative trade to short the dollar and buy oil and other commodities. The second part is the post oil's July peak where oil prices have featured a 60% to $55. Today's wholesale price report shows what happens to prices when supply exceeds demand and banks stop lending money to traders trying to profit from anticipated inflation.

Today's wholesale price report is a doozy. The Producer Price Index (PPI) fell 2.8% in October -- much more than the 1.8% decline economists had anticipated. The PPI decline was fueled (pun intended) by a 12.8% decline in energy prices in October. And as long as those energy prices keep falling, inflation will be in full downswing mode. (I am happy to report that I won my bet that gasoline would drop below $1.99 a gallon in Eastern Massachusetts by February -- I went to a station Sunday that charged $1.97.)

But there's more to it than simply declining oil prices. The entire economy was producing goods and services based on an assumption about demand that depended on easy access to debt. By shutting off the debt flow, goods are simply too expensive for consumers and businesses to pay the price. This means businesses will cut back on production and slash prices to clear their shelves of inventory. Then they'll shut down factories and lay off workers. And the lower demand from those poorer former workers will start the cycle anew.

Peter Cohan is president of Peter S. Cohan & Associates. He also teaches management at Babson College and edits The Cohan Letter.

The Wall Street Journal (subscription required) reports that producer prices launched upward at a 1.2% monthly rate in July. The rise in the PPI -- which was 0.7 percentage points faster than the 0.5% rate economists expected -- was the result of rising wholesale prices for energy spreading to "automobiles, prescription drugs and capital equipment."

Since the price of oil has dropped 24% from $147 to $112, should we all be relieved that July's number is a temporary blip? Let's hope so, because if not, rising wholesale prices make it even harder for businesses to make a profit when consumer demand is weak.

These higher wholesale prices mean that businesses have two options to maintain profits: keep prices the same but cut costs in other areas by finding productivity improvements, cutting back on payrolls and salaries and the likes, or raise prices to offset those rising costs.

The Dow Jones Industrial Average took 208 point nosedive today as investors' confidence, which already was shaken by the subprime mortgage meltdown, further eroded after Wal-Mart Stores Inc. (NYSE: WMT) Chief Executive H. Lee Scott said people will face "difficult pressure economically."

But wait, there's more.

The world's largest retailer also slashed its earnings forecast for the year. Facing panicky investors, money manager Sentinel Management Inc. asked for permission to halt withdrawals by investors. Financial stocks including Citgroup Inc. (NYSE: C), Merrill Lynch & Co. (NYSE: MER), Fortress Investment Group LLC (NYSE: FIG) and Goldman Sachs Group Inc. (NYSE: GS) took a beating.

Prices paid to producers rose 0.6% in July, higher than the 0.2% gain forecasted by analysts surveyed by Bloomberg. The trade gap narrowed 1.7% to $58.1 billion in June, according to the U.S. Commerce Department. Unlike in previous trading days, the Fed didn't pump more money into the market.

But by about 1:20 p.m. Eastern time, the Dow fell more than 125 points to 13,111.27. The NASDAQ Composite Index was at 2,521.99, down 20.9 points. The S&P 500 dropped 15.47 to 1437.45. These dire numbers make it tough to forget that the market is still up for the year -- at least that's the case for now.

The market was looking like it would open up this morning. That is, until 8:30 a.m. when the wholesale inflation report came in at more than twice the rate economists had expected. Now the market is expected to drop. Will the Plunge Protection Team (PPT) step in as it may have done yesterday?

The reason the market reversed is that with higher than expected inflation, the Fed is less likely to cut interest rates. The Fed wants to keep core inflation between 1% and 2%, but when the PPI rises 1.3% in a month -- instead of the expected 0.6% -- investors fear that the Fed will need to raise rates to keep inflation within its target range. Is the Fed serious though? Last week, a productivity report noted that unit labor costs rose 6.6% in the last quarter of 2006. Although bonuses figured into the statistic, the slower growth in productivity suggests that wage inflation could be a future concern.

My guess is, though, that the Fed has a more complex goal -- it's torn between the desire to control inflation and the need to avoid sinking the economy too much. As this report from Fortune suggests, people with adjustable rate mortgages can get into trouble quickly when those rates rise. With two-thirds of economic growth coming from consumer spending, a rise in interest rates could then reduce the heavily leveraged consumer's ability to keep spending.