One in five adults in Britain owns more than one house, according to new figures.
Around 10.3% of adults were in families with multiple property wealth in 2012-14, a 30% increase on 2000-02, analysis by the Resolution Foundation found.
But according to the foundation, owning multiple properties remains a "minority sport"
The proportion of adults in families owning more than one property has surged 30% in the past 17 years, with some some 5.2 million people now owning a second home, the think-tank said.
At the other end of the scale, four in 10 (40%) adults have no property wealth at all, an increase of 35% from 2000-02.
Baby boomers aged 52 to 71 are the most likely to be multiple home owners, accounting for more than half (52%) of all the wealth held in additional properties.
Generation X, made up of 37 to 51-year-olds, accounts for a further quarter (25%) of additional property wealth.
But millennials born since 1981 own just 3% of the additional property assets, the research found.
In 2016, a stamp duty hike was imposed on people buying second homes in England, Wales and Northern Ireland, with changes also made in Scotland, where stamp duty has been abolished, to mirror the rest of the UK.
Laura Gardiner, a senior policy analyst at the Resolution Foundation, said: "Multiple property ownership is still a minority sport, but a growing one that represents a significant boost to the wealth pots of those lucky enough to own second homes.
"People with second homes not only have an investment that they can turn to in times of need, for instance in later life when care is required, but if the property is rented out they also see a boost to their incomes here and now."
The findings were made using a range of figures, including Office for National Statistics (ONS) data.