Gallagher Bassett Services, a subsidiary of Arthur J Gallagher & Co, has signed an agreement to acquire all the third-party administrator (TPA) assets and managed care service operations of GAB Robins North America, and its subsidiary MedInsights, (collectively GABR).

Gallagher said that the transaction does not include GABR’s property/casualty loss adjusting operations, and is expected to close in October 2010.

With the acquisition, around 420 GABR professionals are expected to combine with Gallagher’s property/casualty TPA and managed care operations and will operate under the direction of the company’s president Scott Hudson.

Gallagher expects the GABR acquisition to generate around $45m to $50m in annualized revenue.

Arthur J Gallagher president and CEO Patrick Gallagher said that the strategic combination of the two firms underscores the company’s commitment to invest in and grow this business.