An industry-funded study suggests that brand drug manufacturers are not taking in as much of the gross drug expenditures as they did in previous years.

The study by Berkeley Research Group defines gross expenditures as the sum of all payments for prescription drugs by patients and their health plans prior to any rebates, discounts or fees. The share of those payments received by brand manufacturers has declined from 41 percent in 2013 to 39 percent in 2015, according to BRG’s estimates.

The report, titled The Pharmaceutical Supply Chain: Gross Drug Expenditures Realized by Stakeholders, suggests the reality does not align with public perception and brand manufacturers are earning a lower percentage of the gross spending.