Earnings at Prudential PLC's U.S. subsidiary, Jackson, rose 17 percent in the first nine months of 2011, due in part to a leap in variable annuity sales. The company is now one of the nation's leading providers of the product, which allows policyholders to decide how their savings are invested and then either withdraw cash at the end of the term or re-invest it in an annuity at a guaranteed rate (usually 6%). Given the volume and history of their business, Prudential now offers guaranteed annual withdrawals of around 5 percent of the original account value. The concern? Today's low-interest rates and weak equity markets are driving down returns and eating into capital. In the current market environment, is it safe to offer this kind of guarantee?