The mall still had four anchor tenants, and their leases were tied through a master lease held by Equitable.

Their challenges are now reaching local courts, where early decisions should help boards decide how to deal with unfavorable master leases.

These days, co-ops are finding a ready market for master leases, though the pool of investors is still comparatively small.

"When the residents of a building love a particular tenant," he said, "they'll negotiate a master lease directly with that user."

Among the myriad issues that emerge during negotiations are the projected rent increases over the life of a master lease.

It's just that as a master lease grows more restrictive, its value to an investor declines.

But today he would decline any new master lease with those sorts of controls.

And it has developed a program to make it easier for tenants to take space in multiple markets, using one master lease.

Other tenants said that the master lease speeded negotiations.

A group that holds a master lease on part of the building claims the right to buy and develop the site.