CHICAGO: Marie Callender’s and Hungry-Man are joining together in a deal intended to create a bigger player in the frozen food aisle.

Conagra said Wednesday it is buying Pinnacle Foods for about $10.9 billion, citing in part the potential to capitalize on the recent resurgence of frozen food sales. But investors were skeptical of the combination, and shares of both companies fell.

Conagra also owns the Banquet, Healthy Choice and Alexia frozen brands, while Pinnacle owns Birds Eye, Van de Kamp’s and Mrs. Paul’s. The companies also own other packaged food brands, such as Chef Boyardee, Reddi-Whip and Duncan Hines.

The deal comes amid optimism for supermarket freezer sections after years of disappointing sales. Kellogg reported a jump in frozen food sales earlier this year, citing more millennials focusing on healthier frozen food options. Conagra also said its frozen and refrigerated unit is seeing growth, and CEO Sean Connolly said the category is just starting to benefit from modernization.

The deal also marks the latest shift in the reconfiguration of the U.S. food industry. Big food makers are being pressured by smaller companies that often offer products marketed and seen by consumers as being healthier.

The difficulty large companies have had in increasing sales has prompted established food makers to find other ways to improve financial results.

That includes slashing costs and combining to help merge manufacturing or other operations.