At the end of 2008, I released my Top 10 Stocks for 2009 and the Top 10 Stocks to Avoid. The purpose of both lists was to offer ideas that investors could use to build a portfolio of long and short positions that could be held throughout the year.

The stocks in both reports have performed very well. So far in 2009, the long positions have generated a positive return of more than 7% as compared to a market that is broadly lower. The stocks to sell have in aggregate lost more than 23% in value.

The results combined have greatly exceeded my own expectations. Typically, I'm comfortable letting my winners win and my losers lose through the entirety of the year. That said, the market is far from typical these days.

As such, I wanted to examine some of the biggest winners and losers to determine if locking in gains made any sense. To a certain degree, it may make sense to take action even though the year is only about two months old.

On the long side, the positive returns on the 10 top stocks in the report have been most impressive. The biggest gains so far have come from Tesoro (TSO), Transocean (RIG), Chesapeake (CHK) and Mosaic (MOS).

The gains on these four range from 15% for CHK to 43% for TSO.

The market is very much in the grips of a bear that does not appear to be ending any time soon. There may be rallies within the current bear market, but the bias is for stocks to tread water at best. Therefore, any positive gains, especially double-digit gains, need to be closely monitored.

In this case, the big gainers have come from sectors that I believe will do well irrespective of the general direction of the market. Oil prices can be expected to increase during the year, and demand for fertilizer will coincide with strong global demand for agriculture.

The gains are nice in these four stocks, but let your winners win here. As for the other selections, my opinion for the year has not changed. I would make no changes to this list.

On the short side, there have been even more impressive moves…