Lake Street Advisors, a financial advisory firm for ultra-high-net-worth clients, has joined Focus Financial Partners, an international partnership of independent, fiduciary wealth management firms, Focus announced Monday.

Lake Street, based in Boston and Portsmouth, N.H, is the sixth Focus partner firm in Massachusetts, bolstering Focus’ presence in New England, says Focus.

Co-founders Bob Goyette and Greg Van Slyke formed Lake Street in 2003 to provide family office services to wealthy families.

“Joining the Focus partnership allows us to attain our goal of growing our business for the long-term, better serving the complex needs of our clients and enabling the next generation of leaders at Lake Street,” says Goyette.