The news swept through Goldman's offices around China, changing everything.

On a Friday afternoon in late 2017, an official in Beijing announced that the world's most populous nation would let Wall Street banks expand across its markets. Goldman had spent more than a decade waiting in frustration for that chance. Regional bosses including James Paradise and Todd Leland urgently worked the phones, pinning down details to inform headquarters in New York.

Since then, Goldman Sachs Group Inc. has spoken publicly only in broad strokes about its strategy for China as the gates come down this year. But inside the firm, a massive effort is taking shape.