Plus, that section of the new legislation ends with a puzzling coda. Also excluded are “any trade or business” where the “principal asset” is the “reputation or skill” of its employees or owners. Few are really sure what this means.

“If I put 10 professionals in a room, I’m going to have 10 different ideas of what’s going to be excluded,” said Edward Reitmeyer, a tax partner at accounting firm Marcum LLP.

That kind of confusion creates opportunities to work around the service definitions or to re-cast businesses in ways that arguably fall outside the excluded categories.

Office Real Estate

One strategy being discussed is to combine diverse businesses into a single entity. Let’s say you’re an accountant who also invests in real estate, managing hotels and other properties. Depending on how the IRS writes the regulations, it might make sense to put everything in one company, according to Richard Kollauf, director of business advisory at BMO Private Bank.

Instead of appearing to the IRS to be an accountant -- a service-based profession that wouldn’t qualify for the pass-through break over the income limit -- you look more like a real estate magnate, who would qualify because of large capital investments.

Or, if your business makes the majority of its money through your service profession, the opposite strategy could work. By breaking different businesses apart, service business owners could have at least some of their income qualify for the pass-through deduction. A medical practice might do a fair amount of debt collection or other back-office support. Those divisions could be spun off into a separate “management company,” which could qualify for the break.

Taking it a step further -- service professionals may also consider buying new real estate and adding it to their business portfolios. That’s an option under consideration by Nicholas Sher, a certified public accountant, with offices in midtown Manhattan. Sher said he’s thinking about buying an office condo through a new entity -- which would then lease it back to his firm, Sher & Associates. He could then try to take the 20 percent deduction through the condo entity.

“If I had the right location I would do it in a second,” Sher said.

Business owners who do that may be tempted to drive a hard bargain with themselves -- to maximize the money that qualifies for the deduction. But keep in mind: The IRS has rules about transactions with yourself, and you may have to use market prices.