343 Madison Avenue is a skyscraper under construction in the Midtown Manhattan neighborhood of New York City. The building was designed by Kohn Pedersen Fox for developer BXP, Inc.. The building will replace the former Metropolitan Transportation Authority headquarters across from Grand Central Terminal. As of December 2025, excavation at the site was under way.
Norges Bank Investment Management was an investor in the project, though they later exited the arrangement, returning their investment to BXP for $43.5 million.