Law firm profits may be rising, but rents are rising even faster, according to a new report by commercial real estate services company Jones Lang LaSalle.

The JLL report found that rents for the most premium properties rose more than 18 percent through the end of 2014. Am Law 100 profits, meanwhile, grew 4.6 percent last year.

At the same time, the report notes, law firms are competing with the tech sector and other growing industries for choice locations in cities such as San Francisco, Boston, Miami and New York. Since 2010, Class A rents in core business districts have risen nearly 23 percent, to an average $47.19 per square foot. So-called trophy properties—the most prestigious—saw rents rise to an average of $57.97, according to the report.