People with more wealth tend to report being happier with life, according to a new psychological study of more than 4,000 millionaires.

The study, which was published in Personality and Social Psychology Bulletin, also found evidence that millionaires who earned their wealth were happier than those who inherited it.

“Many people aspire to great wealth, and becoming a millionaire is a commonly used reference for financial success. The question of whether more wealth leads to greater happiness has interested economists, behavioral scientists and the general public for decades,” said study author Grant E. Donnelly, a doctoral candidate in the Marketing Unit at Harvard Business School.

“In general, our understanding is that wealth matters, but there is diminishing marginal utility. One limitation of our understanding is what happens at the higher end—the millionaires of the world,” Donnelly explained. “Individuals with high net worth are hard to get data on, and most of the studies investigating the question of wealth and happiness has used nationally representative samples which do not have a large number of wealthy respondents.”

“We saw an opportunity here to answer this open question and were able to sample high net worth individuals (all reporting a net worth of over $1 million dollars) and to ask them questions about their wealth and happiness. We were able to do this by partnering with a financial service company who specializes in wealth management for high net worth individuals.”

The researchers analyzed two surveys of millionaires from 17 countries. One survey asked the millionaires to rate their happiness in general while the other asked them to rate their life satisfaction.

Donnelly and his colleagues found that substantially higher levels of wealth — having more than $8 million in one survey and $10 million in the other — were linked to greater well-being.

“The general finding is that more money does lead to more happiness,” Donnelly explained to PsyPost. “So, while we’ve believed before there is diminishing marginal utility, the curve doesn’t diminish as quickly as we once thought — and even when basic needs have been met, acquiring more wealth does increase happiness.”

“Another surprising finding is that the source of this money is also important for happiness—participants who reported primarily inheriting or marrying into wealth reported less happiness. It appears that those who earned their wealth attach more happiness to it.”

The researchers believe that wealth might increase happiness by providing a greater sense of autonomy. The more wealth a person has, they argue, the more freedom they have to choose how to spend their time.

However, the study does have some limitations. The researchers used a cross-sectional design, meaning they cannot draw strong conclusions about cause and effect. For example, it is possible that higher well-being leads to higher wealth — rather than the other way around.

“We asked millionaires how much more money they would need to be ‘1’ point happier or a ‘perfect 10’ on the happiness scale, and they predicted a very large amount,” Donnelly said. “Millionaires are correct that they would be happier with more money, but they underestimate the magnitude of their happiness gains from even earning just a bit more money.

“Future research could evaluate how much ‘normal’ earners estimate needing to be 1 point happier or a perfect 10.”

The study, “The Amount and Source of Millionaires’ Wealth (Moderately) Predict Their Happiness“, was co-authored by Tianyi Zheng, Emily Haisley, and Michael I. Norton.