You're probably getting all sorts of conflicting messages these days.

On the one hand, just months ago you heard gloom-and-doom predictions from luminary economists like Nouriel "Dr. Doom" Roubini, calling an S&P 500 bottom possibly as low as 600 -- roughly 40% below yesterday's close. While Roubini has turned less bearish lately, he and most economists agree that we're certainly not out of the woods yet.

At the same time, you have the world's most respected investor, Warren Buffett, saying that now is a good time to buy. Buffett is also putting new money to work, buying shares General Electric (NYSE:GE) and Goldman Sachs (NYSE:GS) preferred stock last fall, and, more recently, Johnson & Johnson and Becton Dickinson.

What's a Fool to do?
With so much debate over what has been roundly dubbed "the worst financial crisis since the Great Depression," I wanted to actually look back at how various strategies fared during each of the other financial crises since the Great Depression.

To get started, I turned to trusty data from Ibbotson Associates, a leading authority on investment research. I calculated the historical returns for cash, bonds, and stocks for those who invested the year following the start of each recession -- roughly the point at which we find ourselves today -- and measured the five-year annualized return for each period.

Here are the results:

Recession

T-Bills

Corporate Bonds

S&P 500

Inflation

March 2001-November 2001

2.3%

7.8%

6.2%

2.7%

July 1990-March 1991

4.3%

12.2%

16.6%

2.8%

July 1981-November 1982

8.6%

22.5%

19.9%

3.3%

January 1980-July 1980

10.3%

17.9%

14.7%

4.9%

November 1973-March 1975

6.2%

6%

4.3%

7.9%

December 1969-November 1970**

5.8%

6%

3.2%

6.9%

April 1960-February 1961

3.1%

3.8%

13.3%

1.3%

August 1957-April 1958

2.4%

3.6%

13.3%

1.3%

July 1953-May 1954

1.9%

1%

22.3%

1.5%

November 1948-October 1949

1.5%

1.9%

17.9%

2.2%

February 1945-October 1945

0.8%

1.8%

9.9%

6.6%

May 1937-June 1938

0.1%

3.8%

4.6%

3.2%

August 1929-March 1933

1%

8.1%

(9.9%)

(4.8%)

Average return

3.7%

7.4%

10.5%

3.1%

Frequency of outperformance

8%

38%

54%

NA

*Data from Ibbotson Associates, Salomon Brothers Long-Term High-Grade Index, National Bureau of Economic Research, Consumer Price Index, and author's calculations.
**Returns calculated from 1971 to 1975.

Rule your recession
Three lessons stand out from this data:

  1. Stocks outperform bonds and T-Bills most of the time, and by large amounts. And remember, these are just averages -- stronger index components like Deere (NYSE:DE) and Walgreen (NYSE:WAG) did even better than the S&P 500 average the last time around.
  2. Unless you need money or plan on investing it, don't park your capital in cash or Treasury bills. If you're bearish enough on stocks to avoid the stock market, history shows that it's much better to invest in a diversified batch of long-term, high-grade corporate bonds. For instance, iBoxx Investment Grade (LQD) is an ETF that invests in the debt of stalwarts like Pfizer (NYSE:PFE) and more resilient financials such as Morgan Stanley (NYSE:MS).
  3. The only period the S&P 500 lost money was the 1930-1934 deflationary death spiral, when deflation ran a chilling 5% annually. Inflation is basically flat, and so long as it doesn't plunge well below zero for an extended time, investors who are looking to buy a diversified basket of stocks today are well-positioned.

But that's not the whole story
Various studies -- including one of my own -- show that small caps tend to outperform their larger counterparts by a significant margin, particularly in recessions. To confirm this, let's look at the table again, this time including small stocks -- defined by Ibbotson as the smallest quintile of stocks:

Recession

T-Bills

Corporate Bonds

S&P 500

Small Stocks

March 2001-November 2001

2.3%

7.8%

6.2%

15.2%

July 1990-March 1991

4.3%

12.2%

16.6%

24.5%

July 1981-November 1982

8.6%

22.5%

19.9%

17.3%

January 1980-July 1980

10.3%

17.9%

14.7%

18.8%

November 1973-March 1975

6.2%

6%

4.3%

24.4%

December 1969-November 1970**

5.8%

6%

3.2%

0.6%

April 1960-February 1961

3.1%

3.8%

13.3%

20.3%

August 1957-April 1958

2.4%

3.6%

13.3%

16.7%

July 1953-May 1954

1.9%

1%

22.3%

23.2%

November 1948-October 1949

1.5%

1.9%

17.9%

11.5%

February 1945-October 1945

0.8%

1.8%

9.9%

7.7%

May 1937-June 1938

0.1%

3.8%

4.6%

10.7%

August 1929-March 1933

1%

8.1%

(9.9%)

(2.4%)

Average return

3.7%

7.4%

10.5%

14.5%

Frequency of outperformance

0%

23%

15%

62%

*Data from Ibbotson Associates, Salomon Brothers Long-Term High-Grade Index, National Bureau of Economic Research, and author's calculations.
**Returns calculated from 1971 to 1975.

Small stocks outperformed T-Bills, bonds, and the S&P about two-thirds of the time -- and they did so by a ridiculous margin. 

But how much dough are we talking about?
A few percentage points might not seem like much, but remember, these are annualized figures. Here's how much money $1,000 invested and held for each five-year period would be worth today, adjusted for inflation:

Asset

Under the Mattress

T-Bills

Corporate Bonds

S&P 500

Small Stocks

$1,000 Would Be Worth ...

$145

$1,505

$13,602

$77,367

$808,984

The data over 13 recessionary periods and various academic studies reveals a powerful lesson: Small stocks really are the best stocks to consider buying in this market. 

Why are small stocks so great?
There are many reasons for why all of the market's best stocks have been small caps. Among the three most prominent are:

  1. Small caps attract less coverage from major brokerage houses and are consequently more likely to be mispriced.
  2. Smaller stocks have more opportunities for growth.
  3. Smaller companies have the ability to be nimbler in tricky situations.

These may also explain why all of the top 30 performers that emerged from the 2001 recession were small or mid caps, including ICICI Bank (NYSE:IBN), Research In Motion, and Titanium Metals, which each rose more than 900%.

Small is good
At Motley Fool Hidden Gems, we look exclusively for niche businesses with wide market opportunities and limited analyst coverage. That's where you're going to find the market's best stocks today. So far, our strategy is paying off -- the newsletter service's average pick is beating the broader market.

If you'd like some help finding superior small-cap ideas, you can check out all of our Hidden Gems stock research, as well as our top small caps for new money, free for the next 30 days.

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This article was originally published on March 13, 2009. It has been updated.

Ilan Moscovitz doesn't own shares of any company mentioned. Pfizer is an Inside Value pick. The Fool's disclosure policy is the best disclosure policy to read before bedtime.