Columbus, Ohio-based Porter Wright Morris & Arthur LLP expanded into the Chicago market earlier this month.The merger with Butler Rubin Saltarelli & Boyd LLP brings an end to the local litigation boutique, which was founded in 1980.Porter Wright managing partner Robert J. Tannous said the firm has gained insurance clients, such as Old Republic Insurance Co. and Fairfax Financial, that can now tap into the resources available from a full-service firm.“Our feeling was that adding Chicago to our Midwest …