Jefferson Wells International drills deep to provide a blowout of professional services in the areas of tax, finance, risk advisory, and accounting. The firm delivers its products through more than 50 offices and serves 40 countries and markets around the world. It also offers temporary staffing -- not surprising, considering its parent is temporary employment titan Manpower. Jefferson Wells serves several Fortune 500 and 1000 companies and targets sectors such as government, energy, financial services, health care, manufacturing, and mining.