The most remote future period taken into account in making economic decisions, such as deciding whether or not to undertake an investment project. Many economic models adopt an infinite time horizon. This is more of a convention than a suggestion that it matches practice, and is often a simplification because many infinite sums have known solutions. For example, the discounted value of receiving an amount B every year into the infinite future when the discount rate is r is given by ${\sum }_{t=0}^{\infty }\text{}\frac{1}{{\left(1+r\right)}^t}\text{}B\text{}=\text{}\frac{1\text{}+r}{r}\text{}B$. In any case, discounting reduces the relative value of future pay-offs, so the difference between a large but finite horizon and an infinite horizon can be practically negligible.