Until recently, condominium applications were a relative breeze. Bank statements, tax returns, and reference letters were the exclusive domain of choosy cooperatives. Increasingly, though, many city condos are upping the ante, asking would-be purchasers to complete longer and more intrusive applications.

While condo applicants need not sit for a board interview, they are often asked for much more than a boilerplate one- or two-page condo applications and a credit check that assured a rubber stamp just a few years ago. Often, personal and professional reference letters, as well as a bevy of notarized documents that attest to their financial well-being, are now required.

At the Bryant ParkTower Condominiums in Midtown, for example, potential unit owners are asked to provide a financial statement, an employment verification letter stating annual salary, the position held, and length of employment; pay stubs from the past 30 days; three reference letters, and a landlord reference letter that details payment history, according to the application.

“You can no longer say to your clients, ‘It’s a condo — it’s going to be easy,'” an associate broker with Halstead Property, Anna Milat-Mayer, said.

In one recent real estate transaction she brokered, an Upper East Side condo asked for extensive financial statements from both her client and from the company that was purchasing the unit on the client’s behalf. “It was a large, well-known company, which wasn’t comfortable providing a full balance sheet — but ultimately it had to,” she said.

Condo boards, through their managing agents, are also taking longer to approve potential tenants, according to Ms. Milat-Mayer. “They’re scrutinizing packages more and more,” she said.

But the change could ultimately benefit condo owners, a broker with the Shvo Group, Ariel Cohen, said. The vetting process could help ensure that a potential buyer has the money to pay the monthly common charges. “It’s a way to protect the building,” he said.

The new requirements have taken many New Yorkers by surprise, an executive vice president of Bellmarc Realty, Janice Silver, said. “They thought it would be like buying a house,” she said of her clients. “They’re saying, ‘Whose business is it? That’s the reason I wanted to buy a condo in the first place — so I wouldn’t have to divulge this information.’ No one is happy about it.”

Troublesome tenants, who, perhaps, don’t pay their maintenance or set up home-based businesses in strictly residential buildings, have impelled boards to screen applicants more carefully, Ms. Silver said.

“I also think it has something to do with real estate prices being so high,” she said. “You’re not paying $200,000 for a one-bedroom apartment. You may be paying $1.2 million, which may be why condos are taking things over the edge.”

Yet, since the likelihood of being turned away by a condo is relatively rare, Ms. Silver said most brokers don’t lose too much sleep over even the most tiresome condo applications. “With condos, it’s more about having money in the bank,” she said. “With co-ops, you have to have money in the bank, and your application still has to look perfect.”

In co-ops, tenants own shares in the building, and the co-op’s governing board can reject applicants without publicly disclosing its reasoning. In condos, individuals purchase units, not building shares. If a condo board exercises its “right of first refusal” and turns down a would-be purchaser, the condo must purchase the unit from the seller.

Most newly constructed condo buildings and recent conversions of older buildings have easier application processes, because they generally comprise owner-sponsored units.

Lengthy condo applications can be a waste of time, a Bellmarc sales agent, Ben Jacoby, said. One current client, he said, has been astonished by the amount of time has gone into completing their condo package. According to Mr. Jacoby, the package required the couple to provide a lengthy financial statement, signed by an accountant, and multiple reference letters. “I knew the board was never going to reject them,” he said. “Still, it ended up taking 40 or 50 hours.”