Why do companies participate in international business transactions?

The
simple answer is that, in this day and age, it is neither practical nor profitable to avoid
doing so. The current global economy is in such a state that you would be very hard pressed to
observe a business transaction involving a service or product that is 100% domestic. As a
consumer, most of the products you consume come from abroad. Even if we're speaking on terms of
manufacturing, raw materials are often imported from abroad.

International
trade can keep prices down and maintain a wide variety of choices in terms of products for
consumers. In the age of the internet, and with the ease of using it to shop, the boons of
international trade have never been more obvious. Frankly, if a company has so much as a web
page, they are engaging in at least a minor form of international trade.