Subleasing and the Office Sublease Overhang

Introduction

Sublease space is the part of office vacancy that does not show up in a landlord's own numbers. A tenant that signed for more space than it now needs, but cannot walk away from the lease, lists the surplus for someone else to take over at a discount. That listed space is still occupied on paper and the original tenant keeps paying rent, yet it competes directly with the landlord's empty floors. Multiply that across a market and you get the office sublease overhang: a pool of discounted shadow supply that has been one of the structural drags on office recovery since 2020.

The overhang is now shrinking. National sublease availability peaked in Q1 2024 at roughly 135 million square feet, the worst sublease overhang since the 2009 Global Financial Crisis, and by early 2026 had fallen to about 101 million square feet, a 13.6% year-over-year decline, roughly 25% below the peak, and the third straight quarter of contraction. Whether that pace holds is the question that matters for office rents, because until the overhang clears, landlords are negotiating against a cheaper alternative on every deal.

Subleases compete with direct leases primarily on price, and the discount is structural rather than incidental. A subtenant accepts a shorter remaining term, since a sublease cannot extend past the head lease's expiration, and typically thinner services, since the counterparty is the original tenant rather than the building owner. The sublessor also cannot match the build-out allowance and amenity package a direct landlord offers. To clear those disadvantages, sublease rents run roughly 15-30% below the building's direct asking rent, and deeper in stressed markets or where the remaining term is short.

For the original tenant, the economics are usually unattractive. Most sublessors recover only 50-70% of the rent they owe under the head lease, eating the shortfall as a real cost; many head leases also carry profit-sharing clauses that route any sublease upside back to the landlord. That is why a tenant with surplus space generally prefers to negotiate a lease termination or a downsizing amendment directly with its landlord, and turns to subleasing only when the landlord will not deal. The choice between those paths is one of the levers covered in office lease economics and the mechanics of effective rent.

Office Sublease Overhang

The accumulated inventory of office space that tenants list for sublease because their space needs shrank but their lease obligations did not. It functions as shadow vacancy: still occupied on paper, but actively marketed at a discount, so it competes with the space landlords are trying to lease directly. National inventory peaked near 135M SF in Q1 2024 and has since declined toward 101M SF, though it remains well above pre-pandemic levels.

A landlord re-leasing an empty floor in a market full of sublease space is not really setting its own price. A prospective tenant can take comparable sublease space nearby at a 20-30% discount, so the landlord either matches that pricing, which compresses effective rent, or holds out and accepts a slower lease-up. Sublease supply therefore puts a ceiling on direct rents that no amount of marketing can lift on its own; the only durable fix is for the overhang itself to drain. The 34M SF absorbed between the Q1 2024 peak and early 2026 is precisely why concessions in the better markets have started to compress rather than widen.

That absorption is deeply uneven. Some markets have seen sublease space fall more than 20% year-over-year as demand returned and tenants pulled listings, while others are still adding inventory as fresh downsizing waves hit. The largest reductions have come in San Francisco, Midtown Manhattan, Dallas, San Jose, and Minneapolis/St. Paul, each a market with a heavy concentration of tenants that either grew back into their space or never fully vacated. The unevenness tracks each market's tenant base, return-to-office posture, and demand recovery, which is why the overhang reads as one indicator within the broader structural transition reshaping the US office sector rather than a single national number.

The pattern is not confined to the US. London's West End and City submarkets, along with major European CBDs, ran up their own sublease overhangs after 2020 as global occupiers rationalized footprints, and those markets are now working through the same absorption process on a similar lag.

Declining sublease inventory is one of the cleaner reads on tenant confidence available in the office market. Listing surplus space is a bet that you will not need it; pulling a listing back into direct use is the opposite bet. The contraction since the Q1 2024 peak says occupiers are increasingly willing to recommit to physical footprints, even with overall demand still running below pre-pandemic levels. The trajectory from here turns on two opposing forces: continued recommitment, which keeps draining the overhang, against any new round of corporate downsizing or recession-driven cuts, which would refill it. The base case among most institutional analysts is gradual absorption with periodic interruptions, slower if the economy weakens but unlikely to reverse outright.