SIOUX FALLS, SD (KELO)–South Dakota’s oldest accounting firm is celebrating its 100th anniversary, a celebration for the longevity of not only the business but also the family continuing its operations.

A look at the long family history of Nelson & Nelson CPAs in tonight’s Your Money Matters.

“My grandfather James Nelson started the business in 1923, he had an office downtown,” Chuck Nelson said.

The original office of James Nelson Accounting Services was just a few blocks away from the original Washington High School where Wesley Nelson grew up.

“He’d come and help my grandpa during the tax season,” Nelson said.

That early exposure planted a seed that eventually led to changing the name to Nelson & Nelson Accountants for the very first time.

“My father [Wesley] after serving in the Korean war joined him in 1957,” Nelson said.

And like his father before him, Chuck Nelson grew up helping his dad and grandpa at the office.

“In high school I’d come down during tax season, we didn’t have computers back then, so I’d type the headings on the tax forms,” Nelson said.

Chuck officially joined the family firm in 1983, continuing the trend of raising his own children with a close connection to the family business.

“It’s home, one person here I’ve known her since I was 10 I think she came in,” Jillian Nelson said.

Out of three girls, Jillian Nelson caught the family’s passion for numbers.

“I loved all my business classes, the accounting, the business law,” Jillian Nelson said.

After graduating from USD, Jillian became the 4th generation of Nelson’s to join the firm.

“I talked with her many times, don’t feel pressure, is this really what you want to do? She knows the hours we work, the stress we go through, especially during the tax season,” Chuck Nelson said.

But both 3rd and 4th generations of the business say they are grateful to be part of a legacy that’s served the Sioux Falls community for the past century.

“To think back that we’ve been around for 100 years and we can pull out tax returns from the 20s. 40s, 70s and 80s,” Jillian Nelson said.

“We’ve got some clients, families that have been with us longer than I’ve been working here,” Chuck Nelson said.

While many area businesses and individuals have had a Nelson working on their books and their taxes for the past century, the demand for their services has only grown.

“When my dad came in there were five employees maybe, some part-time, one was my grandma, she helped. Now we’re up to about 32,” Jillian Nelson said.

A booming business that has had four generations of Nelsons serving clients in the Sioux Falls community and beyond.

“We’re in a pretty small group of businesses that have been able to make it to the 4th generation and 100 years, pretty special to be able to accomplish that,” Chuck Nelson said.

The Family Business Institute says only 30 percent of businesses make it to the 2nd generation, but just 3 percent make it to the 4th generation, making Nelson & Nelson CPAs a very rare find for America’s family-owned businesses.