They wanted to work with nice people, add value to clients’ lives, have fun and, ambitiously, amass $100 million in client assets.

Thirty years later, thanks to a merger announced this month, Buckingham will oversee 1,000 times the assets that its founders envisioned. And its chief executive, Adam Birenbaum, expects it to grow even larger.

Buckingham is merging with Boston-based Colony Group to create a firm with more than $50 billion under management, making it one of the nation’s top 10 wealth-advisory firms. Including a sister firm that handles money for independent advisers, the combined assets will swell to well over $100 billion.

Buckingham and Colony are both owned by Focus Financial Partners, a New York company that’s spent two decades acquiring wealth managers around the country. Private equity firm Clayton, Dubilier & Rice, which bought Focus last year, seems to want to consolidate the 92 firms under Focus’ umbrella.

“The new private equity firm that has invested is creating space for things to be different,” said David DeVoe, head of California consulting firm DeVoe & Co. “They’re rethinking the overall business.”

That spells opportunity, Birenbaum said: “We believe over the next decade we will be able to be a destination for many of those firms, should they desire to join forces, to deliver better outcomes and experiences for their clients.”

Size is increasingly important as independent advisers compete with such giant organizations as Charles Schwab and Bank of America. “There’s power in scale in this industry,” DeVoe said. “Merger activity has been at a record high in the industry, and the No. 1 reason firms give for selling is to gain economies of scale.”

The emphasis on size is a departure for Focus, which used to say it wanted investment advisers to be entrepreneurs, not employees. Birenbaum, though, says the entrepreneurial spirit will remain.

He said 200 of Buckingham’s 700 employees, and about 100 Colony employees, are Focus shareholders. “That ethos continues,” Birenbaum said. “The opportunity moving forward we think is better for our people and our clients than it was on our own.”

The merged firm will have 1,200 employees, including 300 at Buckingham’s headquarters in Clayton. Birenbaum will head the combined entity, which he said probably will adopt a new name reflecting the Focus brand. Colony’s Michael Nathanson will be CEO of Focus.

No headquarters has been announced for the combined firm, but Birenbaum said he’s staying in St. Louis and expects employment here to grow.

“We have a big human organizational design project to do, but further reductions are not part of that,” he said. “We actually believe we will have to expand our teams over the coming years … with the opportunity to build a large amount of the infrastructure and back office here locally.”

At least one familiar name, however, will leave the payroll. Larry Swedroe, the author of 18 books on investing, has been Buckingham’s chief research officer and the architect of its passive, theory-based approach to the markets. Swedroe said he was surprised to learn of his dismissal, but wished his former colleagues well.

“They’re as good of leaders as you’ll find in the industry,” he said. “I’m highly confident the company will continue to do well.”

Birenbaum referred to Swedroe as a mentor, dear friend and “legend in our space.” He said Swedroe’s role would be handled by a new generation of thought leaders, including chief planning officer Jeffrey Levine, chief investment officer Kevin Grogan and research head Jared Kiser.

The merger is scheduled to close July 1. Then, Birenbaum said, “Our job is to thread the needle, to have the benefits of scale and resources but at same time continue to build an organization that feels unique to our people and to our clients.”

To that end, his best guide may be that old one-page plan with its simple goals of having fun, working with nice people and creating value.