SAN FRANCISCO — Orrick, Herrington & Sutcliffe and Pillsbury Winthrop Shaw Pittman won’t be merging after all.

The two firms said Monday that they couldn’t resolve conflicts between Orrick’s public finance clients and Pillsbury’s tax, environmental and real estate practices. “Pillsbury’s client interests are sometimes adverse to the state and municipal interests that we represent. It’s a positional conflict,” Orrick Chairman Mitchell Zuklie said in a joint call with Pillsbury Chairman James Rishwain.