Pittsburgh-based Thorp Reed & Armstrong is in merger talks with Detroit-based Clark Hill, according to several sources across the Pennsylvania legal community.

Talks have been ongoing since last year, and, according to some sources, are expected to be finalized soon.

Thorp Reed Chief Marketing Officer Cynthia Tonet-Stewart said the firm is always exploring new ways to serve its clients, including law firm collaborations. But she said it is a firm policy not to discuss the names of any organization it may be talking to.

“We have many, many discussions with organizations and firms of all kinds,” Tonet-Stewart said, adding again that the firm doesn’t comment on who those discussions are with.

Calls to Clark Hill Chief Executive Officer John J. Hern Jr. were not returned.

At about 100 lawyers firmwide, a merger would most likely mean Thorp Reed would be absorbed by the 220-lawyer Clark Hill, according to Dan Scott, an attorney headhunter with Clarkston, Mich.-based Movement.

But despite the size difference, Scott said the two firms are comparable.“The market vertical they occupy is similar,” Scott said, describing Clark Hill as a general practice commercial firm.

Clark Hill has offices in Detroit, Grand Rapids, Birmingham and Lansing, Mich.; Washington, D.C.; Phoenix; and Chicago. Aside from its Pittsburgh headquarters, Thorp Reed has offices in Philadelphia; Wilmington, Del.; Princeton, N.J.; and Wheeling, W.Va.

With a history dating back to 1890, Scott characterized Clark Hill as an “old-line firm.” In 1996, Clark, Klein and Beaumont merged with Hill Lewis to form Clark Hill. At the time, according to the firm, it was the largest merger of law firms in the history of Michigan.

Consummating a deal with Thorp Reed would be the second merger Clark Hill has undergone in less than a year. In June 2012, the nine attorneys and other staff of the Southfield, Mich.-based law firm Kupelian, Ormond & Magy merged into Clark Hill.

In 2012, Legal affiliate The National Law Journal ranked Clark Hill 205th on its NLJ 350, a ranking of firms by attorney headcount. At that time, Clark Hill had 196 lawyers, including 102 partners and 82 associates.

Noting that the firm has been “reasonably aggressive” in expanding in Chicago, Scott said he’s not surprised Clark Hill would be interested in entering Pittsburgh, where it can market its Detroit rates as a relative bargain.

“They’re looking, like a lot of firms in secondary markets, at expanding into markets where their rates would be considered lower than most big firms,” Scott said, adding that in a market like Pittsburgh, “Being able to say to prospective clients, ‘Hey, we can make money at $450 an hour,’ people are at least going to listen.”

Thorp Reed’s last merger was in 2008 when it combined forces with Philadelphia-based Kittredge Donley Elson Fullem & Embick. Kittredge Donley, with 11 lawyers, expanded Thorp Reed’s presence in Philadelphia as well as its depth in the insurance and reinsurance industry.

After the merger, Thorp Reed had 117 full-time lawyers in Pennsylvania in 2008 and a total of 119 attorneys firmwide, according to Legal affiliate PaLaw 2008. In 2012, according to the latest edition of PaLAW, Thorp Reed had 81 full-time attorneys in Pennsylvania and 95 lawyers firmwide.

Tonet-Stewart said the firm had a “very strong financial performance” in 2012, beating budget on both net revenue and net income. She said the firm is in a “really good position with strong billings” going into 2013.