New research from Parks Associates (http://www.parksassociates.com) finds that subscribers of OTT (over-the-top) services spend more per month renting and buying video downloads than the average household.

This contributes to the success of Amazon's business model of integrating transactional services with its Amazon Prime subscription service, says the research group. Two-thirds of Amazon Prime Instant Video subscribers use Amazon transactional service.

"Amazon Prime subscribers report their expenditure on rented and purchased downloads is increasing," says John Barrett, director, Consumer Analytics, Parks Associates. "Netflix subscribers are more likely to say expenditure in all other categories has decreased-a fact that may reflect Netflix's reliance on a single revenue model. Redbox Instant subscribers, conversely, are more likely to say expenditure is increasing in all categories."