We’re living longer and thriving farther beyond retirement age–and it’s not all beaches and golf courses for those with an entrepreneurial spirit.

A new study from Merrill Lynch addresses the myths and motivations around retirement. Nearly three out of five retirees launch into a new line of work after retirement, according to the study, and working retirees are three times more likely to be entrepreneurs than pre-retirees.

From the study:

After decades of decline, working in later life is making a comeback. Today, 40% of people aged 55-plus are working–a level of engagement in work among this age group not seen since the 1960s. As more people continue working in their later years, the U.S. workforce is steadily transforming. In prior decades, workforce growth was driven by the influx of young workers. In the last seven years, however, workers aged 55-plus accounted for virtually all workforce growth.

They can’t imagine doing nothing for the next 20 years of their lives. Enter the “retire-preneur.”

“Retirement is no longer a distinct moment where a person works for one company for 40 years, has a retirement dinner, gets a nice watch, and then slowly disappears into the sunset,” says Richard Wald, managing director of wealth management at Merrill Lynch. “Retirement today is a much more dynamic and fluid process where people re-invent themselves and go through phases of transition.”

Sociologist and entrepreneur Hal Spielman knows the retirement transition phase well. After over 40 years working at McCollum/Spielman Worldwide, the company he co-founded in 1968, Spielman was inducted into the market research hall of fame. He retired, and his wife died. After a lifetime surrounded by other people–in college, in the Army, at his company and as a married man–being alone was a new, somber challenge.

Putting his market research experience back to work, he studied the lifestyles and challenges of mature, single men in order to help himself cope. That project and his findings became SuddenlySolo.org and the accompanying book.