When you withdraw, you owe federal income tax on the amount of the withdrawal at your ordinary tax rate. And, if you withdraw from any of these plans before you reach age 59 1/2, you'll owe a penalty as well as the income tax that's due, unless you qualify for one of the exceptions spelled out in the federal income tax code. (However, you may be able to borrow from some plans without penalty.)

To be classified as qualified, a plan must provide for all eligible employees equivalently. That means the plan can't treat highly paid employees more generously than it does the least well paid.

In contrast, a nonqualified plan may be available to some employees and not others. Nonqualified contributions are made with posttax dollars, although any earnings in the plan accumulate on a tax-deferred basis. While you must postpone withdrawals to age 59 1/2 to avoid penalty, the federal government does not require you to begin withdrawals at age 70 1/2.

While this type of evaluation is more subjective than quantitative analysis-which looks at statistical data-advocates believe that success or failure in the corporate world is often driven as much by qualitative factors as by financial data.

The Securities and Exchange Commission (SEC) requires all publicly held US companies to publish a quarterly report, officially known as Form 10-Q, describing their financial results for the quarter. These reports and the predictions that market analysts make about them often have an impact on a company's stock price.

For example, if analysts predict that a certain company will have earnings of 55 cents a share in a quarter, and the results beat those expectations, the price of the company's stock may increase. But if the earnings are less than expected, even by a penny or two, the stock price characteristically drops, at least for a time.

Many quasi-public corporations were originally federal agencies that have been privatized. Among the best known are the Federal National Mortgage Association (FNMA) and the Student Loan Marketing Association (Sallie Mae), which securitize mortgages and student loans respectively and sell them in the secondary market. The US Postal Service is also a quasi-public corporation, as is the Tennessee Valley Authority (TVA).

Qubes resemble Standard & Poor's Depositary Receipts (SPDRs), which reflect the performance of the Standard & Poor's 500-stock Index (S&P 500) and the Diamonds Trust (DIA), which tracks the Dow Jones Industrial Average (DJIA).

How that spread is resolved depends on whether the stock is traded on an auction market, such as the New York Stock Exchange (NYSE), or on an electronic market, such as the Nasdaq Stock Market (Nasdaq), where the price is negotiated by market makers.