Q: I live in a co-op in Lower Manhattan. Recently, the board issued a letter requiring a shareholder to add the co-op as an “additional insured” to their homeowner’s insurance policy. The management company also sent an email saying that it needed to be added as an “additional insured.” The insurance company that I’ve had my policy with for decades says it won’t do that. What are the implications of adding either the co-op or management to my policy? What are my options?

A: It sounds like you will need to get a new insurance company.

It’s common in New York City for co-op shareholders to be required to add their co-op and the management company as an “additional insured” on a homeowner’s policy, so this request should not trouble you.

If you have a leak, a fire or another problem that starts in your apartment and travels to the hallway or to a neighbor’s unit, your insurance will usually be the first coverage to step in. When your co-op and management company are also covered on your policy, your insurer can help shield them from legal claims related to the problem that started in your unit, said Tina Larsson, CEO of The Folson Group, a New York City consulting firm.

“It’s not a red flag, it’s not punitive, and it doesn’t give them access to your personal information,” Ms. Larsson said. “It’s simply a layer of protection that helps everyone avoid messy finger-pointing if something goes wrong inside your apartment.”

But some insurance companies — including yours, apparently — will not add additional insured parties.

“The rationale being that they are extending broad coverage to the co-op, which should be picked up by the co-op’s commercial insurance,” said Jeff Schneider, president of Gotham Brokerage Co. Insurers may also be concerned that the shareholder’s coverage would be diluted if the limits are shared by other entities.

Shareholder policies generally do extend coverage automatically to entities that are sued because of the shareholder’s negligence, Mr. Schneider said. You should look at your existing insurance contract to see if it includes this language, and if it does, whether that satisfies your board and management company. This kind of policy sometimes meets the additional insured requirement, he said.

If not, you will need to seek out a new policy, one that can provide you with the required certificate of insurance.