If you love penny stocks (and judging by the number of high impact stocks that have slipped into the penny stock range in the last 18 months … there are a lot of you out there), then the last month has been one of the best optimism or great pessimism.

From March 9 to April 9, the Dow Jones Industrial Average gained 23%, the S&P 500 rose 26%, and the Nasdaq Composite rose 30%. Small-cap stocks significantly outperformed large-caps, and the Russell 2000 Index rose 36% in the same period. According to S & P’s Howard Silverblatt, this has been the steepest 23-day advance since 1933.

The recent appreciation in US equity prices prompted an investment official to say the rally is “too explosive to be sustainable.” According to Birinyi Associates, when small-cap stocks outperform large-cap stocks to this degree after bear markets, rallies fade.

Will history repeat itself? Or will pennies and small-cap stocks continue to trend upward?

According to an article I was reading (and there are undoubtedly ten times as many who point out otherwise), pessimistic views seem to rest on one main assumption: that history is a good guide to the future.

And many times it is. Except in those cases where the story has little or nothing to offer for comparative analysis. While we have all lived to tell the story of the bear markets of the past, it has been a while since we saw something similar to last year.

In fact, it has probably been a century since the economy experienced a sharp drop in the velocity of money as it did last year. Since 1907, the American economy has not experienced a true panic as it did in late 2008.

Larry Summers, President Obama’s top economic adviser, said the economy behaved like a ball falling off the edge of a table in late 2008. Almost all of the important economic data, the article noted, resembles the front half of one V”. from September.

Vehicle sales fell well below the scrapping rate, while home construction fell to just a third of the volume needed to keep up with fundamentals such as population growth. The combination of a rapid decline in economic activity, the rise in foreclosures and mortgage defaults, as well as the adjustment to market accounting led to large losses at banks and panic selling of shares.

If you believe some financial analysts, the economy and the market are recovering from the historically rare events of the past year.

If this is the case, and most stocks are down and trading at what appear to be bargain prices, how can we separate penny stocks from rubbing? After all, even excellent penny stocks saw investors overreact, sending their stock prices off the table. But which penny stocks are going to bounce … and which ones will deservedly fall?

During a normal bearish run, the markets will correctly anticipate the value of many stocks and discount them accordingly. A 50% drop in price is certainly a downgrade, but it’s not a bargain if the value of the business has been cut in half, has deteriorating business units, or is overvalued to begin with.

Last fall, investors hit penny stocks in virtually every sector. The question is, which penny stocks went through a justifiable correction, and which ones were the result of a wrong emotional overreaction?

Here are some penny stocks you may be familiar with. While their stock prices fell off the table last fall, they are financially sound companies that turned into collateral damage, weighed down by bleak market sentiment. And, unlike most penny stocks, their stock prices are rebounding.

Accelrys Inc. (Nasdaq – ACCL) is a profitable and financially sound company with more than $ 53 million in cash, a strong international presence, and no long-term debt. Since the beginning of March, ACCL’s share price has risen 28.57%.

In early February, ACCL announced that third-quarter revenue increased 5% year-over-year to $ 20.6 million. Net income for the period was $ 1.01 million, or $ 0.04 per share compared to a (loss) of ($ 1.23 million), or $ (0.05) per share in the same period last year.

California Micro Devices (Nasdaq – CAMD) is an innovative company with more than $ 48 million in cash, no long-term debt, and good long-term growth potential. Since the beginning of March, CAMD’s share price has risen 39.56%.

In late January, CAMD announced that fiscal year 2009 third quarter results (ended December 31, 2008) set a revised guidance of $ 9.7 million. While demand for the company’s products declined dramatically due to the weakening global economy, the company’s strong balance sheet will help it weather the current economic storm. CAMD expects the current inventory correction to end in mid-2009.

Art Technology Group, Inc. (Nasdaq – ARTG) is a profitable and financially sound company with more than $ 59 million in cash, no long-term debt, and improved operations. In early March, ARTG was trading as low as $ 1.95, and this week it hit an intraday high of $ 2.96; for a short-term spread of 51.79%.

In March, ARTG announced that it signed two strategic partnerships. In early February, the company announced that fourth-quarter revenue increased 16% year-over-year to $ 45.4 million. Net income increased significantly to $ 3.5 million. Annual revenue increased 20% to $ 164.6 million. The company also switched to an annual profitability of $ 3.8 million.

If the recent rally in small-cap stocks and penny stocks is viewed through the lens of recent history, then we could all expect the markets to pull back significantly. Given that the last 18 months have been anything but typical, it is difficult to frame the current optimism of some of the markets.

It’s quite possible that some penny stocks are getting back to where they were last fall, before the emotions kicked in and fell off the table. And that still provides astute penny investors room to maneuver before the actual market rally begins.