A category of stocks for utilities such as gas and power. The utilities sector contains companies such as electric, gas and water firms and integrated providers. Taobiz explains Utilities Sector Because utilities require significant infrastructure, these firms often carry large amounts of debt. With a high debt load, utilities companies become sensitive to changes in the interest rate. As interest rates rise or drop, the debt payments will increase or decrease. The utilities sector performs best when interest rates are falling or remain low.