MFI. An indicator used to show the percentage of a stock's price on up days compared to the total of up and down days. It is an oscillator of money flow. MFI can be calculated following these steps:Typical price = (high + low + close)/3Money flow = typical price * volumeMoney ratio = positive money flow / negative money flowMFI = 100 - (100 / (1+ money ratio)) ORMFI = positive money flow / (positive and negative money flow) * 100(Both formulas arrive at the same MFI value.)Values below 50 indicate that the stock is undersold, while values above 50 indicate that a stock is overbought.