The Flats On D in the Seaport, which has offered one month’s free rent as a tenant incentive.

If you’re one of those lucky Boston renters currently in the market for a high-rise apartment in the sky, you may be in line for further good fortune: Getting paid for your patronage.

The plethora of new luxury apartment buildings coming onto the market simultaneously is prompting landlords and owners to start offering generous leasing incentives to new tenants, according to Boston brokers. The oversupply on the rental side may mean we’re at a tipping point where builders with units under construction will begin to convert their projects to condominiums.

Ever since the wave of new projects was announced, post-housing crash – by some estimates, more than 10,000 new high end units are due to come online in the city over the next few years – some industry observers had raised concerns about whether Boston could absorb them. Up to now, it has certainly seemed to – but that may be changing.

According to Zillow’s rent index, while rents are up 4.1 percent in Boston compared to last winter, they’ve dipped slightly in some of the downtown core neighborhoods which have seen the most construction, falling 6.6 percent in the Fenway, 2.9 percent in Chinatown, 3.4 percent in the Back Bay and 0.6 percent in Downtown itself.

Incentivizing Renters – And Brokers

Brokers say they’re now finding landlords not only willing to cover their fees, but also offering tenant one- or two-month discounts on rent for brand-new, luxury units.

“There is more competition than there has been in many years, with so many new rental units coming online around the same time. All the buildings are offering incentives to lease up,” said Michael DiMella, broker/owner of Charlesgate Realty in the Back Bay. But, he added, “Absorption is moving along pretty well, from what I’ve seen. The Boston economy is strong and demand for living in Boston across the board is very, very healthy.”

“I wouldn’t want to use the word ‘glut’ – the goal is to have as many buildings open as possible, to increase supply and lower rents,” said John Keith, principle at John A. Keith Real Estate in Boston.

“All of these buildings are high end. … The goal was to get top dollar, but they’re all coming online at almost the same time,” and in the off season, to boot, Keith said.

That’s definitely influencing the trend. As many a Boston renter knows, the huge annual influx of students tends to squeeze all renters into the vise-grip of the September-May leasing cycle. With the majority of the tenant pool locking down their digs in spring for the following fall, vacant apartments coming onto the market early in the year often struggle for tenants, even when their price points are aimed more at practicing neurosurgeons than first-year med students.

That incentives are being offered off season gives him little cause for worry, said David Bates, a Boston based William Raveis agent, author of The Bates Real Estate Report, and contributor to Banker & Tradesman.

While he’s definitely seen some slow to rent buildings in outlying neighborhoods like East Boston, most of the new units in the downtown core seem to be being absorbed at a good pace, even if they are offering incentives.

“I’m shocked that they can rent any units at all, considering the winter we’ve had,” he said.

Condo Conversions Coming

But even if there’s external factors influencing the sluggishness on the rental side, landlords may still be glancing jealously at their colleagues in the purchase sector, where inventories are at record lows. The Millennium Tower, the new skyscraper being built at the former Filene’s site downtown, recently announced it has already sold 70 percent of its units, which won’t be ready for move-in until next year.

That kind of demand may be pushing developers to conversions. The Mandarin Oriental, one of the most deluxe existing buildings in the city with several multimillion-dollar sales, announced in November that it would be converting 22 of its units to condos when leases with the current tenants expire. With over 4,000 apartment units currently under development in the city, according to the Boston Redevelopment Authority, more owners may well be tempted to follow their lead.

The decision will be made easier by the current cutthroat competition to provide amenities. With many of the newer buildings attempting to follow Manhattan’s lead and providing 24-hour concierge service, in-building spas, gyms and gourmet restaurants, as well as high-end finishes within the apartments themselves, there’s a much smaller gap between rental and ownership offerings.