First Comes Dimon’s New Tower. Next Up, a JPMorgan Neighborhood

JPMorgan Chase & Co.’s new megatower in Midtown Manhattan will officially open later this month, capping one of the most expensive construction projects in New York history. But when Jamie Dimon, the bank’s billionaire chief executive, cuts the ribbon at 270 Park Ave., he’ll inaugurate something even more ambitious.

Inside America’s biggest city, its biggest bank has been piecing together its own multi-block campus — JPMorgan’s own neighborhood.

As employees settle into the new Norman Foster-designed tower, the bank will pump about $1 billion into renovating the old Bear Stearns offices across the street at 383 Madison Ave., ...