Investors with at least $5 million in assets and minimum annual incomes of $200,000 rank Brown Brothers Harriman of New York City as the top small boutique firm for financial planning and wealth management, according to a new survey by Luxury Institute.

The Wealth Management Luxury Brand Status Index conducted by the New York-based Luxury Institute ranks Brown Brothers Harriman as the top scoring boutique firm with a score of 7.01 out of a possible score of 10.

Brown Brothers' closest competition came from Boston Private Bank and Trust with a score of 6.37; Neuberger Berman Private Asset Management of New York City with 6.3; and Bessemer Trust of New York City with 6.27.

Brown Brothers ranked first in the categories of exclusivity, social status and ability to deliver special client experiences.

"Reputations for honesty and superior client service are what make the smaller firms standouts in this survey," said Milton Pedraza, Luxury Institute CEO.

The 500 survey respondents have $15 million in average net worth and average annual incomes of $720,000. The boutique firms have a much smaller market share than the large Wall Street firms that still dominate the wealth management market, said Martin Swanson, the Luxury Institute's vice president business development.

-Karen DeMasters