Revenues
Wealth management fees increased $112.5 million, or 27.8%, for the three months ended June 30, 2022 compared to the three months ended June 30, 2021. New partner firms added subsequent to the three months ended June 30, 2021 that are included in our results of operations for the three months ended June 30, 2022 include ARS Wealth Advisors, Badgley Phelps Wealth Managers, Ancora Holdings, Sonora Investment Management, Cardinal Point, Ullmann Wealth Partners, Mosaic Family Wealth, Alley Company, Cassaday & Company, Provident Financial Management and Azimuth Capital Investment Management. Additionally, our partner firms completed 25 acquisitions subsequent to the three months ended June 30, 2021. The new partner firms contributed approximately $49.2 million in revenue during the three months ended June 30, 2022. The balance of the increase of $63.3 million was due to the revenue growth at our existing partner firms associated with wealth management services, which includes partner firm-level acquisitions.
Other revenues increased $1.4 million, or 6.9%, for the three months ended June 30, 2022 compared to the three months ended June 30, 2021. Other revenues from new partner firms was approximately $0.7 million. The balance of the increase of $0.7 million was due primarily to an increase in recordkeeping and administration fees.
Operating Expenses
Compensation and related expenses increased $39.1 million, or 28.1%, for the three months ended June 30, 2022 compared to the three months ended June 30, 2021. The increase related to new partner firms was approximately $12.4 million. Non-cash equity compensation increased $1.2 million primarily from equity grants in 2021 and incremental non-cash equity compensation expense from the modification of certain equity awards in 2022. The balance of the increase of $25.5 million was due primarily to an increase in salaries and related expense due to the growth of existing partner firms and partner firm-level acquisitions.
Management fees increased $20.6 million, or 17.7%, for the three months ended June 30, 2022 compared to the three months ended June 30, 2021. The increase related to new partner firms was approximately $10.8 million. Management fees are variable and a function of earnings during the period. The balance of the increase of $9.8 million was primarily due to partner firm-level acquisitions and the increase in earnings during the three months ended June 30, 2022 compared to the three months ended June 30, 2021.
Selling, general and administrative expenses increased $25.8 million, or 37.3%, for the three months ended June 30, 2022 compared to the three months ended June 30, 2021. New partner firms added approximately $8.3 million. The balance of the increase of $17.5 million was due primarily to an increase in expenses related to travel and entertainment, professional fees and information technology expenses related to the growth of our existing partner firms and partner firm-level acquisitions.
Intangible amortization increased $20.6 million, or 46.9%, for the three months ended June 30, 2022 compared to the three months ended June 30, 2021. The increase related to new partner firms was approximately $12.8 million. The balance of the increase of $7.8 million was due primarily to partner firm-level acquisitions.
Non-cash changes in fair value of estimated contingent consideration decreased $76.8 million for the three months ended June 30, 2022 compared to the three months ended June 30, 2021. During the three months ended June 30, 2022, the probability that certain contingent consideration payments would be achieved decreased due to Monte Carlo Simulation changes associated with market conditions and forecasts, resulting in a decrease in the fair value of the contingent consideration liability.
Other income (expense)
Interest expense increased $9.1 million, or 83.7%, for the three months ended June 30, 2022 compared to the three months ended June 30, 2021. The increase was due primarily to higher average outstanding borrowings during the three months ended June 30, 2022 compared to the three months ended June 30, 2021.
Income Tax Expense
Income tax expense increased $30.1 million for the three months ended June 30, 2022 compared to the three months ended June 30, 2021. For the three months ended June 30, 2022, we recorded tax expense based on an estimated annual effective tax rate of 35.1%. The estimated annual effective tax rate is primarily related to federal, state and local income taxes imposed on Focus Inc.’s allocable portion of taxable income from Focus LLC and reflects an estimated valuation allowance of $9.0 million for deferred tax assets relating to business interest carryforwards.