Peter Swan thinks mum-and-dad investors have been maligned for far too long – and he has the numbers to prove his case.

In the research paper, Other People's Money: Mum and Dad Investors Versus the Professionals​, the UNSW Business School professor of finance and his co-authors – Wei Lu, also from UNSW Business School, and Joakim Westerholm from the University of Sydney Business School – analyse data covering almost the entire equity portfolios of every investor on a daily basis in Finland during a 17-year period.

The trio believes the study is a first in that they examine the matched trades between entire investor classes, covering households, domestic institutions and foreign institutions.​

And the result? "We demonstrate that households are the winners against all opponents, followed by domestic institutions, with foreign investors always the losers," the authors state in the paper.

Furthermore, they find that households that do not delegate all their equity investment to professional managers are likely to be the most successful long-term traders.

According to Swan, the analysis shows that mum-and-dad, or individual, investors have been "unfairly treated for the past 35 years or more" through biased research and commentary.

Read the full story at UNSW's Business Think.