This is the third time the group has advocated voting against JPMorgan's executive compensation since the Dodd-Frank law mandated shareholders be given a say on pay in 2010. Each time, ISS has cited discretionary compensation as a concern.

JPMorgan, the largest U.S. bank by assets, did not immediately provide comment on the ISS view.

The bank's board of directors recommended in its proxy filing that shareholders vote to approve executive compensation at its shareholder meeting next week in Chicago, based on the company's strong business results, risk controls and conduct, customer and stakeholder focus, and leadership in 2018.

The influential proxy advisory firm said that although JPMorgan's compensation committee uses performance assessments to guide the amount of discretionary compensation awarded, certain "factors assessed were described only vaguely and appear subjective."

"Investors increasingly prefer an incentive program structure that constrains discretion in favor of emphasis on objective and transparent determinations that are more compatible with pay-for-performance," ISS wrote.

ISS said it was also concerned about the vesting of one part of the pay plans described as performance share units.

ISS previously advised voting against executive pay in 2015 because it objected to a discretionary cash bonus, and in 2011 because it said the chief executive pay was "significantly above-median" and the discretionary components reduced the focus on performance.

JPMorgan Chief Executive Jamie Dimon, who has led the bank since 2005, received a total of $31 million in compensation for the year 2018, $1.5 million more than in 2017. His compensation included an annual base salary of more than $1.5 million and performance-based incentives of $29.5 million.

The shareholder vote on executive compensation next week is ultimately nonbinding. However, the bank's board said in its 2019 proxy statement that it will consider the results of the vote when making future compensation arrangements.

In Britain, Standard Chartered faced investor criticism at its annual shareholder meeting on Wednesday after roughly a third of votes were cast against its executive compensation plans.

Standard Chartered's pay plans differ significantly from U.S. banks. ISS and another advisory firm, Glass Lewis, had advised shareholders to vote against the plans.

(Reporting By Elizabeth Dilts; additional reporting by David Henry in New York; editing by Bill Berkrot and Jonathan Oatis)

By Elizabeth Dilts