You are the CFO and Treasurer of Hitech Corporation. In January of each year, Hitech normally has around $500,000 more cash than it needs to meet current obligations. But in June, current obligations require the availability of that $500,000 plus another $250,000 from a line of credit loan. Rather than let the $500,000 sit idle in a non-interest bearing checking account, in what type of investment would you invest the $500,000 in January, and why?