In Greene’s Pressure Treating & Rentals, Inc. v. Fulbright & Jaworski, L.L.P., 178 S.W.3d 40 (Tex. App. – Houston [1st Dist.] 2005, no pet.), the Fulbright firm had provided a non-infringement opinion to a corporation. Later, certain assets of that corporation were acquired by a third-party. Fulbright was then retained by the patentee to sue that third party for infringement. The third-party settled the case, but then sued Fulbright for breach of fiduciary duty. Fulbright obtained summary judgment because the third party had only acquired certain assets of Fulbright’s former client, and so had not succeeded to the attorney-client relationship between Fulbright and its former client.
In addition to adversity with a "former client," a “pulling punches” claim could be brought by the recipient of the opinion, contending the firm was materially limited in its ability to give an objective opinion due to its obligations to the owner of the patent. Clearly, opining about clients’ patents presents risks.
The suit against Fulbright also suggests that firms ensure that conflicts databases include patent numbers and perhaps inventors’ names (to catch CIPs, for instance) for any patent that is the subject of an opinion of counsel by a firm. While it may be appropriate to undertake litigation for infringement of a patent that a firm had previously stated was not infringed under the facts presented, the possible litigation costs that could arise, along with the competency issues that could be raised by the patentee, indicate that this should be a matter of concern for outside counsel.