There's a good chance you're making a simple mistake when it comes to money, Vanguard says. How to make sure you're not missing out on any gains.
A majority of Americans are earning less than 3% on their cash savings, Vanguard data shows.damircudic/Getty Images Many Americans miss out on high-yield savings due to a low of awareness of interest rates. A Vanguard survey shows 57% of p…