Usually. Almost all co-op buildings in NYC permit some degree of subletting. Even if a co-op does not formally permit sublets, they may consider a subletting request from a shareholder due to financial hardship or a personal emergency.
Most co-op buildings in NYC will allow an owner to sublet for one to two years every few years. There is almost always a required initial owner occupancy period before a building allows subletting. Stricter co-op buildings will only permit subletting for a few years during the lifetime of ownership.
Co-ops with stricter subletting policies tend to be less expensive, as the subletting restrictions turn away buyers and ultimately reduce demand. Even if a prospective buyer has no plans to leave NYC, she or he will probably be turned off by a strict co-op sublet policy. After all, if a co-op is tough on sublets then it’s not a stretch to assume that they’ll be difficult on renovations and extremely harsh with enforcing building rules and levying penalties.