It refers to the proportion of income the fund portfolio returned in the past twelve months. It is a significant figure but often is ignored. It provides details related to internal audits, financial analysis, and corporate planning. The term can be found in the company’s balance sheet where it may be updated quarterly ( as per GAAP rules).
Financial experts may use it to scrutinize the balance sheet, to examine the figures related to the income statement and cash flows, and they use everyday live market data of the stock price to recommend measures or actions.
For example- A company reporting revenues of $1bn is considered good for investment but the one that was able to maintain the same amount of revenue in the last 12 months is consistent and reliable. The performance of the last 12 months indicates the growth charts trajectory or different asset classes.