This document discusses uncovered interest rate parity (UIRP) and covered interest rate parity (CIRP), which relate interest rates between countries to exchange rates. UIRP refers to parity when exposed to exchange rate risk, while CIRP uses forward contracts to eliminate exchange rate risk. The document provides an example where UK interest rates are 2% and Japanese rates are 1%, requiring the pound to depreciate 1% against the yen to avoid arbitrage opportunities. It also discusses purchasing power parity (PPP), which estimates exchange rates needed for currencies to have equal purchasing power based on market baskets of goods. PPP helps minimize misleading international comparisons that can arise from using market exchange rates alone.