As Election Day approaches, real estate and development groups are worried that Bloomberg-era tax incentives and subsides will leave with him.

For the past decade, Mayor Bloomberg has been a friend to business in City Hall, rezoning a third of the city, largely in favor of commercial projects and their supporting residential developments. In the name of job creation, the city has pumped billions of dollars in cash incentives and forgone revenue to help companies expand their operations in the five boroughs.

The frontrunner in the race, Bill de Blasio, has laid out plans that could mean a radical shift from the business-friendly New York City of recent years. New Yorkers are worried that Mr. Blasio’s populist rhetoric will bring the city back to the dark days of businesses fleeing the city.

“There’s an underlying premise in the de Blasio playbook that there’s so much momentum behind the City of New York that the lack of incentives is not going to be material,” said Kenneth Fisher, a land use attorney and former councilmember. “That worldview will either be sustained because the economic boom will continue or he’ll have to come to grips if constructions starts to go down, or if he loses a landmark New York corporation.”

The Bloomberg administration’s $130 million subsidy of grocery-delivery company FreshDirect became a flash point in a recent mayoral debate when, on a question about job creation, Joe Lhota criticized Bill de Blasio’s disapproval of the subsidy.

FreshDirect received a package of funds from various levels of government when they threatened to decamp from their Long Island City location for New Jersey in 2010. The Bloomberg administration coupled with Governor Cuomo to find a plot of land along the Harlem River in the South Bronx that could facilitate the company’s expansion. In exchange, FreshDirect pledged to create 1,000 jobs at the new facility, a third of which would go to local residents where the unemployment rate is highest in the city.

“You cannot talk about creating jobs if you’re going to export jobs across the border,” Mr. Lhota said. “Bill, I don’t understand how you can sit there and talk about what you’re going to do when you were given a chance to actually save jobs in New York and you said no, you wouldn’t have done it.”

The package of incentives given to FreshDirect has been one of the more controversial of Bloomberg’s term, and the candidates’ reaction to it give an indication of how they would direct future subsidies.

Mr. de Blasio has called for the dismantling of the Department of Finance’s Industrial and Commercial Abatement Program – from which FreshDirect received nearly $50 million in tax abatements and exemptions.

He wants to restrict subsidies to corporations, and require that companies receiving city support provide “living wage” jobs. Robert S. Altman, an attorney and lobbyist for the building trades, said that would mean union jobs and increases to the already high cost of construction.

“The problem with doing a lot of what he wants to do with prevailing wage is that it raises the cost of doing business,” he said. “I don’t think he can serve every master here and he’s going to have to make a choice between the unions and poor people.”

Mr. Altman has done work for FreshDirect and would not comment specifically on the deal, but said that the real estate industry is concerned that Mr. de Blasio – and the new council – could diminish the motivation for investing in the local economy by making development prohibitively expensive.

“There are politicians in New York who are as bad on the left as the Tea Party is on the right,” he said. “And our concern is that they’ll have too much voice in the next city government.”

While the subsidies are not always necessary for a business to operate, they can be vital for a company that wants to expand its workforce or move to a larger space.

“The context for all of this is that construction costs in New York are a third higher than the rest of the country,” said Mr. Fisher. “These subsidies can make all the difference between success and failure.”

In addition, both Mr. de Blasio and Mr. Lhota have called for increased transparency at the Economic Development Corporation, a non-profit operating outside the city government. In 2011, the Independent Budget Office released a report – at Mr. de Blasio’s behest – that said poor reporting by the EDC made it impossible to gauge the economic impact of the non-profit’s projects.

Bettina Damiani, project director at Good Jobs New York, a public subsidy watchdog, said that transparency from the agencies is key to reform. Being open about where the money goes and keeping track of jobs created are “part of a three-legged stool,” she said.

“Right now, it’s like these projects are cooked up in some back room at City Hall,” she said. “They need to be based on the needs of low-income communities.”

His populist message has previously put Mr. de Blasio at odds with the real estate industry.

But in a possible sign of warming, Mr. de Blasio has appeared in recent weeks at a number of meetings with pro-business groups to deliver his message of a “tale of two cities.”

Some analysts see the fledgling relationship between Mr. de Blasio and the business community as less cordial than resigned acceptance. With a 45-point lead in recent polls, Mr. de Blasio seems the inevitable victor, with or without real estate’s support.

“They are realistic about the outcome of the election,” Hunter College professor of political science Kenneth Sherrill said of the real estate industry. “They would rather be on the good side of the winner than not.”
But Mr. Sherrill was doubtful that capital projects would grind to a halt without the subsidies.

“The means of funding capital projects may vary, but there is no question that capital construction will happen,” he said. “No matter who wins, they win.”