By now, it's common knowledge that the recession is over; Warren Buffett implied it back in September. Hold on, writes Gluskin Sheff chief economist David Rosenberg, in a commentary this week: Judging by the criteria that the NBER itself uses, that conclusion is anything but assured (the NBER is the official arbiter of recessions in the U.S.). That should be a sobering observation for share investors since it's entirely inconsistent with a powerful rally that has lifted stocks 64% from the March 9 market low.

Nailing down the recession end
The NBER views "real GDP as the single best measure of aggregate economic activity." However, official GDP results are only available on a quarterly basis, which isn't granular enough for the NBER to determine the beginning and end months of a recession. As such, the NBER also looks at monthly GDP estimates produced by Macroeconomic Advisors. While those numbers do suggest that the recession ended in June, the most recent data for the four other main indicators the NBER looks at tell a different story, with three of four lower than in the prior month:

Indicator

1-Month % Change
(Oct. 2009, preliminary)

Suggests Recession
Has Ended

Employment

-0.1%

FAIL

Personal income less government transfer payments

-0.03%

FAIL

Industrial production

+0.1%

PASS

Manufacturing and trade (wholesale/retail) sales

-0.2%*

FAIL

*September 2009 is the most recent value.
Source: Bureau of Economic Analysis, Federal Reserve, and Bureau of Labor Statistics.

S&P 500 aggregate real revenues down 9% year-on-year
Even if the recession did end in the third quarter -- which would largely be due to government spending -- aggregate revenues for the current members of the S&P 500 in the third quarter were still 9% lower than the previous year on an inflation-adjusted basis, with only one in three companies exhibiting positive real revenue growth. Among the top 5% of S&P companies on the basis of Q3 revenue growth, you'll find:

Company

Calendar Q3 2009 Year-on-Year
Revenue Growth (Inflation-Adjusted)

American International Group (NYSE:AIG)

2,606.4%

Goldman Sachs (NYSE:GS)

108.1%

Citigroup (NYSE:C)

61.5%

DeVry (NYSE:DV)

44.3%

Apollo Group (NASDAQ:APOL)

31.5%

Amazon.com (NASDAQ:AMZN)

29.9%

Apple (NASDAQ:AAPL)

27.1%

Where fools rush in
Is the recession over? My guess is that it did end at some point in the third quarter, but even if that turns out to be the case, it should provide no encouragement to stock investors to pay current prices for the U.S. stock market. Indeed, investors have been bidding the market up to levels consistent with a robust recovery in the face of economic data that suggest any recovery will be weak and protracted. Don't be tempted to rush headfirst into the fray now -- steeling your nerves and remaining patient is the better course.

The new reality for the U.S. is slow growth and rising budget deficits and public debt. Global Gains co-advisor Tim Hanson urges you to get out now to mitigate those trends.

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Alex Dumortier, CFA, has no beneficial interest in any of the companies mentioned in this article. Apple and Amazon.com are Motley Fool Stock Advisor recommendations. Apollo Group is a Motley Fool Inside Value pick. Try any of our Foolish newsletters today, free for 30 days. Motley Fool has a disclosure policy.