Activist investor Daniel Loeb is testing the cohesion of the family that has controlled Campbell Soup Co. for more than a century with his push to unseat the board and potentially sell the company.
Mr. Loeb’s campaign to replace the soup maker’s board, announced last week, needs backing from descendants of John T. Dorrance, the inventor of Campbell’s condensed soup. The family holds at least 45% of the company’s stock. Additionally, two-thirds of shareholders would need to approve the full sale that Mr. Loeb has called for,...