The NMA research examined six key aspects of financial advertising - retailers' financial products, mortgages, credit cards, finance, loans and insurance.
National newspapers donated the equivalent of £22m in ad space, filled by Sheilas' Wheels, Churchill, Norwich Union and Barclays, to test various approaches.
The NMA found that, when advertising campaigns ran across newspapers and television, the response in a given geographical area more than doubled compared with just a television campaign alone. The study also revealed that newspaper ads were seen as more reliable and trustworthy than online or television.
NMA spokesman Tom Lynch predicted that the amount financial service providers allocate to newspapers would double on the back of the study, because "we have independently proven how much more effective these campaigns are".
The full report will be presented to media agencies across the country over the next few weeks.