Baby boomers are the nation’s second-largest living generation, overtaken only recently by millennials. Even though many boomers have technically reached retirement age, that doesn’t mean they’re ready to stop working just yet. More and more individuals age 50 and older are choosing to embark on encore careers instead by starting their own small businesses.

As a leading provider of 401(k) business financing, my company, Guidant Financial, has seen its fair share of boomers making the jump from employee to employer. We’ve found that the market is exploding with niche opportunities that not only jive with boomer interests but have the ability to be extremely profitable. Here are the top five business industries in which we’ve seen boomers thrive:

  1. Pet care. Many boomers have chosen to fill their empty nests with four-legged, furry companions, and starting a business in this lucrative market not only allows aspiring entrepreneurs to pursue their passion for critters, but make money at the same time. Americans as a whole spent $55.7 billion on pets in 2013, and that number’s expected to creep up in the coming years.
  2. Travel. One of the biggest boomer trends is to visit destinations they haven’t seen before while they still can, making travel a growing arena. Travelers were expected to spend up to $65 billion in 2015, up 7 percent from 2014, so businesses in this industry, whether it’s a vacation planner or a rental car company, can expect to cash in on that revenue. Baby boomers can even choose to be Airbnb hosts and make some extra cash on the side by renting their space to travelers.
  3. Campgrounds and RV parks. Spending time outdoors and reconnecting with nature after years in a corporate office is a love many boomers share. RV parks, which allow owners to experience the great outdoors while also making a profit, are a great way to marry the two interests. According to IBISWorld, the RV park industry has steadily grown since 2010, raking in $6 billion in revenue in 2015.
  4. Senior care. Unfortunately, as boomers are aging, so are their parents, so the need for senior care is expanding. “Aging in place” is becoming increasingly popular as seniors strive to stay in the comfort of their own homes for as long as possible, making in-home care services especially profitable. The senior care market has seen 12.6 percent growth over the last five years to 2015 and is worth $13 billion.
  5. Fitness. Baby boomers care about their health and want to stay in shape to avoid aging and disease. As such, the fitness industry has seen a large movement of 50+ individuals not only joining gyms, but also starting their own fitness-related businesses. As millennials are also increasingly health conscious, the amount of money spent on fitness continues to increase, and the industry as a whole is worth $27 billion as of January 2016. From gyms to fitness-related technology, this is one industry that’s good for boomers’ heath and their pocketbooks.

Whether it’s a new business concept or a franchise, these five industries are a great solution for baby boomers to invest in themselves, pursue their passions and make a profit as they continue to work beyond retirement.