The results come amid the backdrop of the bank's decision to break from its wealth management peers and wind down its commissions-based retirement business and the departure of 145 financial advisers from Merrill Lynch's "thundering herd."

The firm committed to ending its IRA accounts last year in preparation for the US Labor Department's fiduciary rule that takes effect on June 9 and requires firms to eliminate potential conflicts of interest for advisers managing client's retirement accounts.

"These solid results were produced in a period of change for the industry as firms and clients anticipate new fiduciary standards and other market dynamics such as the shift between active and passive investing," Donofrio said on a call with analysts.

The bank's Global Wealth and Investment Management division, which includes Merrill Lynch and US Trust, reported long-term assets under managed rose to $29.2 billion in the three months ended March 31 from $18.9 billion in the fourth quarter last year.

The unit's pretax profit margin, a key metric that can show growth across business segments, rose to 27 percent from 26 percent a year earlier.

Overall, the second-largest US bank's total revenue rose about 7 percent to $22.45 billion, beating the estimate of $21.61 billion.

Last month, Merrill Lynch partly walked back its statement that it would completely end commissions-paying retirement accounts after the fiduciary rule was delayed by 60 days from the original implementation date of April 10.

Nonetheless, the portion of advisers with more than half of their clients enrolled in fee-based accounts, which pay an adviser a flat-fee rather than a commission, continued to rise this quarter, up 2 percent to 66 percent of advisers compared to the prior quarter.

Brokerage and other non interest income fell $83 million over last year as the firm moves away from commissions-paying accounts.

Donofrio acknowledged that transactional revenue continued to decline, but said it was offset by higher assets under management and fees.

Merrill Lynch revenue rose 5 percent to $3.78 billion from the prior quarter on higher asset management fees and net interest income. The firm's total number of advisers fell to 14,484 from 14,629 in the fourth quarter last year.