In a blow to Campbell, investor advisory firm Institutional Shareholder Services came out in support Wednesday night of activist firm Third Point's efforts to put five of its nominees on the soup company board.

In the ruling, ISS criticized the soup company for poor performance, which it said "appear directly linked to shortcomings in the company's acquisition strategy, poor execution of mergers and a lack of focus on the company's core business."

ISS is typically an influential guide on how institutional shareholders should vote. Still, Campbell remains very much a family company, with descendants of the soup company's founder retaining a significant stake.

Campbell Soup heirs who hold roughly 41 percent of the company's shares have already come out in support of Campbell. Three descendants currently sit on the Campbell board.

Nonetheless, ISS pointed to a number of missteps it said the company made under its current board, underlined by its financial performance. The company delivered a roughly 19 percent total shareholder return over the last two years, while the S&P 500 has nearly tripled in the same period.

"Given the board's subpar oversight of critical issues such as M&A and succession planning, shareholders may wonder whether the incumbent board is capable of steering Campbell back on track in a timely manner," according to the ruling.

Campbell is currently unwinding efforts to diversify into fresh foods, selling brands it spent more than $1 billion on under the leadership of former CEO Denise Morrison. After struggles due to their inexperience with fresh food and an ill-timed drought, its fresh food unit posted an operating loss of $7 million last quarter.

Meantime, Campbell's $6.2 billion acquisition of pretzel and chip company Snyder's-Lance more than tripled the company's debt burden and brought with it a business that will be challenging to integrate.

The soup company, continues to stand by the deal — interim CEO Keith McLoughlin told analysts in August that the company is "even more convinced of the growth prospects and synergies."

ISS also raised questions about Campbell's dedication to its dividend, despite its poor financial performance.

"Maintaining the dividend may prove to be the right decision, though it raises the question of whether the board, which currently includes three members of the founding family, is truly considering all options," the ruling stated.

Third Point — which recently trimmed its board nominees from twelve to five — has nominated Sarah Hofstetter, president of Comscore; Bozoma Saint John, chief marketing officer of entertainment conglomerate Endeavor; Kurt Schmidt, a former director and CEO of Blue Buffalo; William Toler, former CEO of Hostess Brand and Third Point executive Munib Islam.

Campbell spokesman Thomas Hushen said in a statement Wednesday night the company strongly disagrees with ISS's conclusion.

"The Campbell board consists of 12 members, 11 of whom are independent and four of whom have been added since 2016," Hushen said.

The board combines the necessary skills — including a strong mix of industry experience, operating expertise, long-term shareholder perspectives, financial acumen, and global public company experience — needed to provide the proper oversight and strategic guidance on a variety of diverse consumer and business needs amid rapid changes in the food industry.

Interim CEO McLoughlin said last week the company proposed adding two of Third Point's nominees to its board, Kurt Schmidt and Sarah Hofstetter. McLoughlin said Third Point rejected that option.