OptionsXpress Holdings, Inc. (NASDAQ: OXPS) announced it will pay a special dividend before the end of the year so investors can take advantage of favorable dividend tax rates while they last. Specifically, OptionsXpress will pay out a dividend of $4.50 per share – about $260 million in total and more than 26% of the company’s present share price. The special OXPS dividend is payable Dec. 27 to shareholders of record Dec. 13, so there is still time to share in the OptionsXpress special dividend.

Dividends are nothing new for OptionsXpress, a small-cap brokerage service and investor education company. OXPS has returned over $100 million to its shareholders through buybacks and dividends since early 2008. The reason behind this generosity is simple: Without many logical acquisition opportunities or game-changing growth plans, the promise of big special dividends keeps shareholders happy.

It’s worth noting, however, that OXPS isn’t just dipping into its cash reserves. The special dividend comes from a $120 million four-year variable rate term loan to cover part of the dividend. OptionsXpress Holdings will keep $125 million in its coffers (in cash and investments) even after the special dividend.

Options trading strategies have really come into their own in recent years, thanks in part to sophisticated trading techniques at a time of immense market volatility and uncertainty. As many investors have evolved beyond the old buy-and-hold mentality, OptionsXpress has been a valuable resource for these traders.

So is OptionsXpress itself a good investment? That depends. OXPS stock has tacked on about 12% so far in 2010, more than double the gains of the broader market, though it is essentially flat over the past 18 months, excluding brief periods of peak and trough. Still, even if the company remains flat for some time, a massive special dividend may make the investment a decent move for many portfolios.

Jeff Reeves is editor of InvestorPlace.com. Follow him on Twitter at http://twitter.com/JeffReevesIP.