The number of British people who own a second home, buy-to-let or overseas property has doubled since 2001, says think tank the Resolution Foundation.
While the number of millennials who own a home continues to fall, one in 10 people now own an additional property.
Just 37% of people born in the 1980s managed to buy a home at the age of 29, compared with half of those born in the 1960s.
Wealth from owning a second home has risen since 2001 to almost £1 trillion.
Buy-to-let property is now the most common form of property wealth, having grown by 58% since 2006-08, the report found.
However, when looking at the number of people who can afford an additional property, millennials match the property ownership rates of other generations.
The government said it was helping first-time buyers get on the housing ladder.
“The Government is determined to ensure that a new generation can realise the dream of homeownership,” a spokesman said.
“Last year saw the highest number of first-time buyers in more than a decade. Since 2015, we have helped more than 300,000 people to purchase a home through schemes such as Help to Buy.”