Millionaires are taking to social media in surprising numbers-especially to Facebook (FB).
Three-fourths of millionaires in a Spectrum Group survey said they use social media. The wealth research firm said 57 percent of the 1,300 millionaires in the poll responded that they use Facebook, while 41 percent use LinkedIn (LNKD) and 10 percent use Twitter (TWTR).
"The wealthy are using social media at almost the same rates as the nonwealthy," said George Walper, Spectrem's president.
Read More How to stay rich for three generations
Indeed, age and occupation tend to be better indicators of social-media use than wealth. Among millionaires under age 35, 81 percent use Facebook, 65 percent use LinkedIn and 32 percent use Twitter.
Roughly half of millionaires age 65 or older use Facebook, while 32 percent use LinkedIn and 5 percent use Twitter.
For all platforms, however, social media growth among millionaires is slowing. Millionaire use of Facebook grew from 26 percent to 55 percent between 2010 and 2013 but remained relatively flat in 2014. LinkedIn use doubled between 2010 and 2013 to 34 percent and hit 41 percent in 2014. Twitter use grew from 5 percent in 2010 to 10 percent in 2014.
Read More Look who backs a 4-day workweek
Among those who don't use social media, most (53 percent) said it was because they "see no value" in using them. Half said the programs were a "waste of time" and raised concerns about their privacy.
Overall, business owners are more active on social media than other professions. Senior corporate executives are the biggest users of YouTube (GOOGL) and LinkedIn.
Millionaires vary widely, however, on how often they actually use social media. About 1 in 5 use Facebook less than once a week and about half use it once a day or more. Among millionaire Twitter users, a third use it less than once a week and 38 percent use it daily.
What do millionaires use social media for? Plenty of baby pics and vacation photos, no doubt. But they also use it for news and financial information. Among millionaire Twitter users, 36 percent follow athletes, which tied with "news commentators" for the largest category.
A quarter follow movie stars and only 12 percent follow financial or investment commentators.
Walper said those numbers show a big opportunity for wealth managers, who have yet to really embrace social media as a way to communicate with clients.
"Financial advisors and advisors are still shying away from letting folks use social media," he said. "They should be using it more. It's a great tool to communicate their message."
The subjects in the survey have at least $1 million in investible assets.
-CNBC's Robert Frank