The Aug. 31 announcement of Pacific Century Group Inc.'s $500 million agreement to buy American International Group Inc. asset management unit AIG Investments was notable not just because it marked resolution to a rocky sales process, but also because it left out one detail: Goldman, Sachs & Co.

Goldman bankers Donald Truesdale and Charlie Lockyer advised the buyer on the sale, sources say, but their firm was left off the final press release, a casualty of some backroom jostling during the auction. According to a source, both Goldman and boutique adviser Perella Weinberg Partners LP negotiated for the bidders throughout the auction, which reportedly began in January, but advisory credit in the announcement went solely to Perella Weinberg.

That firm was brought in by Pacific Century's CEO and Hong Kong billionaire Richard Li, who also asked Perella's asset management arm to invest in the deal alongside private equity firm Crestview Partners LP when Franklin Templeton Investments withdrew from an initial bidding consortium. Perella was invited into the consortium in July as a 20% investor to act as a "tiebreaker" between Crestview and Pacific Century, says a source. This led to some wrangling between Goldman's bankers and Perella's team of Joseph Perella, Peter Weinberg and Titus Leung.

As the auction dragged on, some members of the bidding consortium, which had gained the exclusive right to acquire the asset management unit, dropped out as they became uncomfortable with collaborating with Li, a source says. That ultimately left Pacific Century as the sole suitor. Li's preferred adviser, Perella, got the advisory credit; Goldman, which a source says was hired by Crestview, lost out.

AIG and Crestview didn't return calls. Representatives for Perella and Goldman Sachs declined to comment.

For legal advice, Pacific Century turned to Skadden, Arps, Slate, Meagher & Flom LLP's Ralph Arditi and Michael Dorum, who came on board with the original bidders in the early summer. Skadden remained at the buying group's side after Franklin Templeton dropped out.

AIG's legal counsel, Debevoise & Plimpton LLP, was also a constant throughout the auction. Partner Gregory Gooding says the auction process accelerated in the last week or so, adding, once there was one buyer, "it made it easier to get to the finish line." Gooding was joined by colleagues Peter Furci and Jonathan Lewis on the deal.

AIG's financial advisers on the deal were UBS Investment Bank's Bradford Hearsh, Robert Glauerdt and Ashley Park. UBS had also advised AIG on its sale of Swiss bank AIG Private Bank Ltd., announced in December, to Aabar Investments PJSC of Abu Dhabi.