The use of forecasting, and, in particular, using time series forecasting, goes beyond the scope of a few stocks. Hence, in this chapter, we will also cover the forecasting of portfolios. A portfolio can be defined as simply a range of investments held by a person or organization. An individual may have multiple stocks. Thus, the need to look at the scenarios where investment in a single stock needs to be assessed against holdings in other stocks. Certainly, there must also be other investment instruments that a person can hold. What about gold, bonds, real estate, and the now in vogue cryptocurrencies, such as Bitcoin?

Most organizations deal with multiple items in a portfolio. These items are usually spread across asset and liability classes. The portfolio usually isn't compiled in a day. It evolves over a period of time, and there are entrants and leavers. There is also competition among the various constituents of a portfolio. Are this year's retained earnings for a company going to be invested in fixed deposits, or are a part of the earnings going to be invested in government bonds? There's bound to be questions about the best avenue for investing the money. At the time of investment, the most logical choice would be to go for the option that offers the highest rate of return.