(Update with information about Netezza's buyout and impact on Radware.)NEW YORK ( TheStreet) -- Despite a few ups and downs the major stock indexes are up about 1% year-to-date. Among the gains -- of which there were many -- a number of specific stocks are now considered overbought and may be ripe for a sell. A stock is generally considered overbought when high demand unjustifiably pushes its price higher than its underlying fundamentals support. It may also mean the stock's price has risen so much, and usually on high volume, that an oscillator's upper boundary has been reached, according to Investopedia. That usually indicates the equity's price is overvalued and due for a pullback.