Annuity sales are exploding higher as retirees look to lock up guaranteed lifetime income in an environment where fewer folks leaving the workplace have a traditional pension. In a sign of wise planning, easy-to-understand basic income annuities are among the fastest growing of these insurance products. In all, net annuity sales reached $56.1 billion in the first quarter—up 13% from a year earlier, based on data reported by Beacon Research and Morningstar. Variable annuities, often seen more as a tax-smart investing supplement for the wealthy than a vehicle for lifetime income, account for most of the market. These annuities, which essentially let you invest in mutual funds with some insurance guarantees, saw first-quarter net sales of $33.5 billion—down slightly from a year ago. (For more on the cost and potential risks of variable annuities, click here and here.) Meanwhile, net sales of fixed annuities, which offer more certain returns, surged to levels last seen in the rush to safety at the height of the Great Recession—totaling $22.6 billion for the quarter. Fixed annuities come in simple and complex varieties—those indexed to the stock market can be confusing and laden with fees. But the subset known as income annuities—the most basic and straightforward of the lot—grew at a 50% clip versus 44% for the index variety. Basic income annuities, also known as immediate annuities, remain a tiny portion of the overall $2.6 trillion annuity market. Yet they are what most investors think of when they ponder buying an income stream. With an immediate annuity you plunk down cash and begin receiving pre-set guaranteed income over a period of, say, 10 or 20 years, or life. Rates have been relatively low, as they are for most fixed-income investments. Recently a 65-year-old man investing $100,000 could get a lifetime payout of 6.6%, according to ImmediateAnnuities.com. Another type of fixed annuity, called a deferred income annuity or longevity annuity, lets you put down a lump sum in return for income that starts years later —think of it as a form of insurance for old age. Though less well known, longevity annuities are increasingly popular, with sales reaching $620 million in the first quarter, up 57%, according to LIMRA, an insurance marketing research group. You can find other types of annuities designed lock up income, but the amount of the payout is often a moving figure and the fee structure can be difficult to understand. Lifetime income has emerged as perhaps the biggest retirement challenge of our age. The gradual shift from defined benefit plans to defined contribution plans over the past 30 years has begun to leave each new class of retirees without the predictable, monthly stream of cash needed to cover basic expenses. The push is on to help these retirees convert their 401(k) and IRA savings to a guaranteed income stream. But innovation is not coming fast, and traditionally many investors have been reluctant to tie up their money in fixed annuities. So the quarterly sales trends are heartening. They suggest that individuals are acting to shore up a critical aspect of their retirement plan.