Limits on shares?

Q Is the number of shares of a company that can be bought limited in any way? — H.D., Lake City, Florida A Yes, indeed. For starters, companies don’t have unlimited shares. They issue a certain number when they go public via an “initial public offering” (IPO), and they may issue more later, via secondary offerings. (The more shares that exist, the smaller stake in the company each one represents.) A company might have only a portion of its value in shares trading publicly, too. If its founder, for example, holds, say, 51 percent or 65 percent of the company, then she still controls it. You could buy all available shares of a company, but by doing so, your sudden demand for the shares would drive up the price. (That’s why major investors don’t want to publicize their trading, and why they try to buy gradually, in increments.) Of course, that’s costly. Clorox, for example, has about 130 million shares outstanding, and you’d need more than $15 billion to buy them all.

Additionally, once anyone owns more than 5 percent of a voting class of shares, he must file a report alerting the Securities and Exchange Commission. Q Must I sell my IRA stocks at age 701⁄2? — T.S., Honolulu A You have to take “required minimum distributions” from traditional IRAs once you turn 701⁄2. They’re generally taxable, and you may need to sell some stocks or other holdings in the IRA to generate the cash to withdraw.

Roth IRAs have no RMDs. And if the Roth IRA is at least five years old and you’re older than 591⁄2, distributions are taxfree. Learn much more about IRAs at fool.com/retirement/index.aspx.