(MONEY Magazine) – For years, financial advisers and publications, including MONEY, have recommended dollar-cost averaging -- a technique in which you regularly put the same amount of money into a mutual fund or other investment, regardless of market moves, thus reducing your average cost per share. Although dollar-cost averaging is a wise way to invest out of a weekly paycheck, two new studies suggest that it can be costly if you have a pension payout or other lump sum to invest. An analysis by Cincinnati investment adviser James Gore indicates that keeping most of the money in a low-yielding account while feeding it into the investment slowly can shave your annual returns by 2.2 percentage points, compared with investing a sum all at once. And two Wright State University professors found that you'll make more money plunking the whole sum into the market about two-thirds of the time. "Because the market trend is usually up, you are almost always better off investing the entire sum at once," says one of them, Richard Williams. But since odds are there will be a market correction soon, many investment advisers recommend against investing a lump sum all at once right now. Sheldon Jacobs, editor of the No-Load Fund Investor newsletter, favors putting half a lump into a conservative stock fund, such as Gabelli Asset (800-422-3554), and investing the rest gradually over six to 12 months.