How many shares?

QIs the number of shares of a company that can be bought limited in any way?

— P.L., Lawrence, Kansas

AYup. Each publicly traded company has a certain number of “shares outstanding” — and that number stays fixed until or unless it issues more shares, buys back shares or splits its shares.

Companies first issue shares when they “go public” via an initial public offering (IPO). They sometimes issue more later, via “secondary” offerings. (The more shares a company has, the smaller stake in the company each share represents.)

In theory, you might try to buy all available shares of a company, but in the process of doing so, your demand would drive up the price of the shares. (This is why big investors such as Warren Buffett don't publicize their purchases, and why they try to buy chunks of shares over time.)

Buying all the shares of most companies would be very costly, too: FedEx, for example, recently had around 259 million shares outstanding, and a recent share price of $233. To buy all those shares, you'd need around $60 billion.

Q

What is “Nasdaq”?

A— K.W., Arlington, Virginia

The National Association of Securities Dealers Automated Quotation system (NASDAQ) was launched in 1971 to help investors access stock prices. It later became the first electronic stock market through which investors could trade shares.

The Nasdaq Stock Market is now the largest electronic stock market, where more than 5,000 companies are listed. These include Costco and Starbucks, as well as lots of technology-focused businesses, such as Amazon. com, Apple, Microsoft and Netflix. The other main U.S. stock market is the New York Stock Exchange.