Though the merger talks could continue on for several more weeks, the two companies have been negotiating exclusively with each other in recent days, Variety reported.
Sources with knowledge said bids for Summit are in $350 million to $400 million range plus the assumption of some Summit debt.
It is understood that should Lionsgate acquire Summit, Summit heads Rob Friedman and Patrick Wachsberger would remain in top-level positions within the merged entity. The pair transformed Summit from a foreign sales company into a full-service production and distribution studio after their profitable gamble on film adaptations of Stephenie Meyer's best-selling series of vampire novels in 2007.
The merger comes as Lionsgate prepares to release "Hunger Games," the first installment a series of feature films based on the popular book series. The film, which opens March 23, is hoped to revitalize Lionsgate's film slate.
The last of Summit's "Twilight" franchise, "The Twilight Saga: Breaking Dawn -- Part 2," due to open Nov. 16, is estimated to bring in as much as $1 billion at the worldwide box office.