The document discusses functional currency, which is the currency of the primary economic environment where a company operates. A company's functional currency may differ from its home or reporting currency. To determine functional currency, management considers factors like autonomy of foreign operations, volume of transactions in various currencies, proportion of cash flows in each currency, and debt service currency. An example given is of a Chinese company with its largest market and revenues in US dollars, making the US dollar its functional currency rather than the Chinese yuan.