Merger and acquisition (M&A) and corporate restructuring are a big part of the corporate finance world. Every day, Wall Street investment bankers arrange M&A transactions, which bring separate companies together to form larger ones. When they're not creating big companies from smaller ones, corporate finance deals do the reverse and break up companies through spinoffs, carve-outs or tracking stocks. Not surprisingly, these actions often make the news. Deals can be worth hundreds of millions, or even billions, of dollars. They can dictate the fortunes of the companies involved for years to come. For a CEO, leading an M&A can represent the highlight of a whole career. And it is no wonder we hear about so many of these transactions; they happen all the time. Next time you flip open the newspaper’s business section, odds are good that at least one headline will announce some kind of M&A transaction. Sure, M&A deals grab headlines, but what does this all mean to investors? To answer this question, this tutorial discusses the forces that drive companies to buy or merge with others, or to split-off or sell parts of their own businesses. Once you know the different ways in which these deals are executed, you'll have a better idea of whether you should cheer or weep when a company you own buys another company - or is bought by one. You will also be aware of the tax consequences for companies and for investors The Main Idea One plus one makes three: this equation is the special alchemy of a merger or an acquisition. The key principle behind buying a company is to create shareholder value over and above that of the sum of the two companies. Two companies together are more valuable than two separate companies - at least, that's the reasoning behind M&A. This rationale is particularly alluring to companies when times are tough. Strong companies will act to buy other companies to create a more competitive, cost-efficient company. The companies will come together hoping to gain a greater market share or to achieve greater efficiency. Because of these potential benefits, target companies will often agree to be purchased when they know they cannot survive alone.