Marielle Schurig spoke to a group of women at a wellness event at Lululemon in New York's Flatiron district after a yoga and circuit-training class. Following her remarks, attendees lined up for an hour to talk to her about their finances.

The women told Schurig, an account vice president at UBS Financial Services, that they let their spouses or partners decide on money matters. Despite investing hours in self-care, many of the self-proclaimed feminists admitted that they had taken a back seat in their own financial affairs.

That is common: 59 percent of women ages 20 to 34 defer investing and financial planning to spouses, according to a survey by UBS Group AG. The Swiss bank found that younger women are more likely than earlier generations to give such leeway to their partners.

"I was really surprised to see that," Schurig said. "You see women fighting for equal rights and equal opportunities, for respect in the workplace and at home. There's all these women running for political office. We continue talking about breaking glass ceilings. But once we make the money and get those positions, what are we doing with it?"

Younger women often don't include financial health as a factor in their well-being, said Schurig, a regular at SoulCycle.

"Women will spend a lot of time researching the best skin care, makeup product — they're not sitting down and examining their financial life," she said. "It'll be hard for us to be fully equal with men if we're not on the same financial page as them."

Indeed, UBS Global Wealth Management polled 3,652 women globally with a minimum of $250,000 in investable assets. Millennial women cited other responsibilities as being more urgent than investing and financial planning.

The study found that women are overwhelmingly involved in day-to-day money matters, with 80 percent paying bills and 85 percent regularly managing expenses. Yet all around the world, that engagement did not extend to longer-term finances.

About 82 percent of women of all ages told UBS that they thought men know more about investing and financial planning. The proportion of younger women deferring financial decisions to their spouses was lowest in Brazil and Mexico and highest in Switzerland, Hong Kong and Singapore.

In a separate S&P Global survey of almost 10,000 Americans, only 26 percent of U.S. women said they make investments even as 41 percent say now would be a good time to be active in the markets.

Nguyen and Kim write for Bloomberg.