Jackson Walker, the largest Texas-only law firm, is representing Texas burger chain Whataburger as it agrees to sell a majority interest to BDT Capital Partners of Chicago.

Norton Rose Fulbright represents BDT Capital Partners, a merchant bank that advises and invests in family and founder-led companies and was founded by former Goldman Sachs banker Byron Trott, who has advised such investors as Warren Buffett. The purchase price was not disclosed.