Always invest your company's revenues; operating funds can be put into conservative overnight vehicles like repurchase agreements or commercial paper. Typically, these investments will earn about 5%, but remember, they're only for money that is readily needed. Funds that are not required for daily expenses can be put into CD's or bonds which earn a bit higher interest, about 6-8%. Keep in mind that the higher the return on investment, the higher the accompanying risk. That's why operating funds should always go into the most conservative of investments. A financial institution or advisor should be able to help you structure an effective portfolio that provides for expenses while also helping money you earn to grow.