Can any company be bought?

In theory, any company can be bought for the right price. Publicly-traded companies (companies with stocks listed on a national exchange like the New York Stock Exchange or the NASDAQ) can theoretically be acquired through acquisition of stock on the open market. Privately held companies (companies with stocks that are owned by less than 500 investors to avoid certain federal listing requirements) can be acquired by negotiating directly with the stockholders to acquire their shares of stock. However, many corporations are protected by "anti-takeover" provisions that prevent people from simply buying a majority of the company's stock and taking over the company. These anti-takeover provisions may be in the company's charter or bylaws (legal documents that describe how the company is organized and run) or they may be actual state or federal laws (several states prevent an individual or group from buying a significant chunk of stock without the approval of a company's board of directors).

In addition, public companies with stock listed on stock exchanges are required to register that stock with the US Securities and Exchange Commission (the SEC). The SEC has a substantial set of rules in place about how stocks can be bought or sold in US markets - primarily in an effort to protect stockholders from unfair practices.

Companies are also often subject to other types of regulation. For example, a power company can't simply sell itself to the highest bidder - because it is a utility and people rely on it to get electricity to their homes, various federal and state agencies generally must approve the sale of those companies (such as the Federal Energy Regulatory Commission). In addition, to prevent the formation of monopolies, buyers of large companies must generally apply to the Federal Trade Commission and US Justice Department for antitrust review. If the FTC is concerned that a merger of two large companies will result in lower competition in a certain field, they may prevent the merger until they have reviewed the market and decided the merger will not result in significant harm to consumers or, in the alternative, they may prevent the merger altogether. A current example of this is the proposed merger of Sirius Satellite Radio and XM Radio, which is still under review almost a year after the proposal was originally announced in February 2007.