WITH the prospect of significant changes in tax rates and deduction limits, taxpayers have been coming up with all sorts of strategies to save on their taxes, some riskier than others.

So I couldn’t help but be skeptical when I was told about a plan aimed at small-business owners in their 50s who have saved little for retirement but can now afford to put aside a lot of money each year. They can then deduct that money as a business expense, resulting in a significant tax savings.

But I checked with the Internal Revenue Service, and the plan is indeed legitimate.

It is a defined-benefit plan, much like the one large employers once regularly offered their workers, that guarantees a set monthly payment in retirement. In this case, though, the plan works best for really small businesses — those that employ just one or two people.

The I.R.S. allows a maximum annual contribution to the plan of about $255,000 for people in their 50s. (For younger workers, the contribution limit is lower, because the calculation is based on the number of years until retirement. In some cases, the limit is so low that other retirement savings options might be better.) Total holdings in the plan are limited to $2.3 million to $2.4 million, enough to cover the maximum allowed payment in retirement of $200,000 a year.