As part of the filing, three of Third Point's nominees to Campbell's board revealed stakes in the soup giant: Lawrence Karlson, Michael Silverstein and William Toler.
Shares of Campbell rose 1 percent in after-hours trading following the news.
Third Point announced its intention to try to replace the entire Campbell board earlier this year. Third Point is unhappy with Campbell's performance and claimed it didn't fully evaluate a potential sale as part of the company's three-month critical review.
The review was sparked by Campbell's disappointing earnings and surprise departure of CEO Denise Morrison. While Loeb has pushed for Campbell to sell itself as part of the review, Campbell announced in August that it plans to sell its international and fresh food businesses.
Loeb is now trying to replace all 12 of Campbell's board directors at the company's Nov. 29 shareholder meeting. The company on October 4 reiterated its support for its own band of board nominees, which include three descendants of the company's founder: Archbold van Beuren, Bennett Dorrance and Mary Alice Malone. Dorrance and Malone together hold 33 percent of Campbell and have resisted past pressure to sell the company.
It also took aim at two of Third Point's nominees, both of whom were prior Campbell board members. One of them, George Strawbridge Jr. is a descendant of a founder. Strawbridge has disclosed a 2.7 percent stake in Campbell and has partnered with Third Point in its campaign.
"Despite criticisms of oversight at Campbell, Third Point nominated George Strawbridge, Jr., who retired from Campbell's Board at the age of 72 in 2009, with a tenure that spanned more than 22 years, and Lawrence Karlson, who served on the Board as recently as 2015 and supported many of the acquisitions that Third Point is now criticizing," the company said in the documents.