The combination won't affect Stinson's Kansas City office, a spokeswoman said. That office has 197 attorneys and 276 staff members. The combination will be effective July 1, subject to due diligence and a review of potential client conflicts.

"We are always looking for what is best for our clients and providing them with the best service and expertise possible," Mark Foster, Stinson's managing partner, said in a release. "Blumenfeld Kaplan & Sandweiss is an excellent law firm with a top-notch team of lawyers. Our clients will benefit from the synergies created as a result this combination."

Stinson traces its heritage to 1878. The firm opened its St. Louis office in 1994. The firm's lawyers have extensive experience in real estate law, mergers and acquisitions, labor and employment, business litigation, financial services, health care, sports law and product liability.

Blumenfeld was established in St. Louis in 1950 by John Blumenfeld, a prominent real estate lawyer who continues to be active with the firm. Today, it ranks among the 15 largest law firms in St. Louis. Its main areas of practice include real estate, tax, estate planning, succession planning, mergers and acquisitions, immigration, labor and employment, intellectual property and litigation.

"The potential benefits for our clients created by this combination with Stinson Morrison Hecker are significant," Philip Kaplan, president of Blumenfeld, said in the release. "Our practice has continued to grow on the local, national and international stages, and this combination will allow us to provide additional talent that will expand and enhance the efficient delivery of legal services."

Stinson ranks No. 2 on the Kansas City Business Journal's list of area law firms. Blumenfeld is tied at No. 15 with Lashly and Baer PC on the St. Louis Business Journal's list of area law firms.