NEW YORK (TheStreet) -- With the stock market virtually rising without pause for more than three years, investors who want to follow the gospel of buying low and selling high are stymied at almost every turn.

So why bother? Instead, buy high and sell higher.

Must Read: 10 Stocks Billionaire David Einhorn Loves for 2015

To be sure this strategy is full of risks, but some funds that effectively take this approach are pulling it off with spectacular results.

The strategy is known as momentum investing, and it takes two huge skills to succeed. One is to find highly volatile stocks that are going up fast.

Think emerging markets, high-growth, high-tech and small-cap before the 30 corporations that make up the Dow Jones Industrial Average.

The market is considered inefficient for these generally lesser-known companies.

Eventually though, the market is likely to take notice, say, if there are higher-than-expected quarterly earnings. Such announcements often lead securities analysts to write glowing reports, investors to demand the stock and the price to leap, in other words, momentum.

Getting out is as important as getting in. Having a quick trigger and being ready to pull it is an essential part of a successful strategy.

In stock market terms, it means portfolio turnover is high.

Reasons to get out include a breakdown in fundamentals and choppiness in the movement of share prices.

Must Read: Jim Cramer on the Stock Market: Investors Need to Own Up and Regroup

But the risks are numerous and deep, too. These stocks may be thinly traded and so hard to sell.

Also, because an incredible number of stocks are involved -- coming and going -- it is difficult to stay on top of developments. The slightest slip will cause the market to pound a stock that built up great expectations before the fund can react.

Sometimes the fund won't just go down with the stock but out, too. As it is, generalists are rarer than funds that focus on a particular sector -- say, emerging or technology -- of the market.

A hot hand in a hot sector or even across the market can produce impressive results, though. Among those funds that have swamped the S&P 500 over the past two to three years with gains of from 50% higher to three times as high are Fidelity Select Biotechnology Portfolio (FBIOX) , First Trust Health Care AlphaDEX (FXH) , iShares MSCI USA Momentum Factor (MTUM) , iShares NASDAQ Biotech (IBB) and SPDR S&P 1500 Momentum Tilt (MMTM) .

Must Read: Consider the Source: Asset Managers Seen a Better Bet Than Funds

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.

If you liked this article you might like

Investors Finally Get the Break They’ve Been Expecting for a Long Time

Investors Finally Get the Break They’ve Been Expecting for a Long Time

Fidelity's Red-Hot Sector Funds

Fidelity's Red-Hot Sector Funds

Is Your 401(k) Ignoring These Hot Sectors?

Is Your 401(k) Ignoring These Hot Sectors?

Cramer's 'Mad Money' Recap: 'Timber!'

Cramer's 'Mad Money' Recap: 'Timber!'