Adding support to the trend, older companies that have several motivations to hang onto unused space are putting plenty of sub-lease supply on the market, says Learner. “There's a glut of sublease space,” she says.

Citing an example of one such offering, Tiffany & Co. took more space that it needed at 200 Fifth Ave., Learner says, locking in current rates while it planned to sublease the space. “The company still has the ability to grow into space when they need it, and meanwhile it has recouped some of its real estate costs,” she says. The famed jeweler subleased the space to social media website BuzzFeed back in April.

Technology firms tend to sign shorter subleases—but they tend to agree to take the space at a faster clip—than firms in other sectors, the report states, making them particularly desirable sublease tenants. Tech firms have an average sublease term of 4.4 years, one year shorter than the average sublease term for non-tech tenants, while tech tenants finalized sublease agreements an average of 8.8 months after a space was listed, while non-tech firms took nearly 2.5 months longer on average to acquire their space.

“In general, we're seeing technology companies in a hurry to move from the space they've outgrown,” Learner says.

This subleasing trend appears to be a win/win for the tenants involved, but it can create a problem for landlords, she notes. “This creates more competition for landlords with direct leasing space. The sublease space will eventually dwindle but, in the meantime, landlords are going to need to offer flexible terms.”