“When you can't increase the top line, you're looking to reevaluate the bottom line,” Mitchell Marcus, managing director for Jones Lang LaSalle in the Philadelphia CBD market, tells GlobeSt.com exclusively. “That's coming in from efficiencies and the densification of office space for all users.”

While many office space users are shifting from traditional “perimeter office” space to open office configurations, law firms have been lagging in this trend, Marcus says.

“Due to the nature of the way law firms work, that model just doesn't function for them,” says Marcus. “It's a little less collaborative and a little less group-oriented, and the need for privacy, so with the world going to open plans, collaborative benching, densification to the tune of 150-175 square feet per person, law firms are still in that perimeter office mode with less ways to drive those efficiencies and savings.”

In Philadelphia 15% of the class A office market is currently occupied by law firms, and while tenant demand profiles have shifted from large- to mid-sized users, sub-six percent trophy vacancy has positioned class A landlords to benefit as a result of previous rental growth.

Headcounts at Philadelphia law firms are relatively stable, says Marcus. Right sizing is coming mainly from moves to more flexible office designs and more pooling of support staff. Support staff ratios are moving from 2 professionals for every support person to 3 and four professionals per support person, he says.

Recent law firm mergers affecting Philadelphia firms have not had a significant impact on the size of local office space, because the mergers have not been overlapping, Marcus says. JLL is seeing smaller and more consistently sized offices, more glass being used for office walls than before, and the use of interior offices for support personnel, he says.