Intellectual Ventures, the mother of all patent holding companies, is the type of deep-pocketed client that a lot of firms might shy away from. That’s especially true for firms with that do a lot of business with established tech companies like those that IV or its proxies have targeted in a wave of patent infringement suits over the past year.

Though it’s only filed eight complaints since first turning to the courts in December 2010 to enforce its massive patent portfolio, IV has already tapped a varied roster of firms including Feinberg Day Alberti & Thompson; Susman Godfrey; Weil, Gotshal & Manges; Desmarais LLP; and Irell & Manella. Now a new firm has joined the list: On Thursday Dechert filed a Delaware federal district court suit for Intellectual Ventures claiming that AT&T, Sprint, and T-Mobile infringe 15 IV patents related to wireless technology.

“We previously attempted to discuss licensing options with each of these companies, but none were responsive,” Melissa Finocchio, IV’s chief litigation counsel, said in a statement. “We filed a complaint for infringement today in the U.S. District Court of Delaware to get these three companies on a course toward compensating IV for the value of the inventions they use in delivering their wireless services.”

Notably absent as a defendant in the lawsuit is Verizon, the largest wireless carrier in the United States. A spokeswoman for Intellectual Ventures confirmed that Verizon Wireless has agreed to license for the patents.

IV’s business model hasn’t always made for a good match with large defense-focused firms like Dechert. In 2009, Wilson, Sonsini, Goodrich & Rosati dropped Intellectual Ventures as a client after the firm began hearing complaints from several large publicly-traded technology clients that faced patent infringement claims by non-practicing entities, or so-called patent trolls. The potential risk of Intellectual Ventures one day suing a Wilson Sonsini client was just one of the factors thefirm considered, according a June 2011 ruling disqualifying Wilson Sonsoni from representing an IV defendant.

Martin Black of Dechert, the lead lawyer on IV’s latest complaint, did not respond to a request for comment. An Intellectual Ventures spokesperson confirmed that Thursday’s filing marked Dechert’s first representation of the company. Dechert has operated in Silicon Valley, where many of IV’s litigation targets are based, since 2003.

This article originally appeared in The American Lawyer.