LONDON — In a symbolic backlash against high at a money-losing company, shareholders have voted against the $19.6 million compensation package for the chief executive, Robert W. Dudley.

Though it was a nonbinding vote that will not affect Mr. Dudley’s pay for the year past, a BP spokesman said on Thursday at the annual shareholders meeting that investors had sent “a message to the board” that might influence deliberations on a new pay policy. The policy will be submitted to shareholders at the annual meeting next year, in a vote that will be binding, said the spokesman, David Nicholas.

Investors have chafed at Mr. Dudley’s receiving a 20 percent increase in overall compensation, despite a $6.5 billion loss reported by the company for 2015, as sharply lower oil prices exacted a severe toll on profits.

According to BP, the tally of proxy votes cast before Thursday’s annual general meeting in London was 59.1 percent against and 40.9 percent in favor.

There are still additional votes to be counted, but they are unlikely to significantly alter the proportions, Mr. Nicholas said.

As is legally required at British companies, the BP chief executive’s pay is determined by a formula that is put to a vote by shareholders every three years. BP’s current formula was approved by about 96 percent of shareholders in 2014, Mr. Nicholas said.

At Thursday’s meeting, Carl-Henric Svanberg, BP’s chairman, told shareholders that the board was aware of their concerns.

“Let me be clear: We hear you,” Mr. Svanberg said, according to a transcript provided by BP. “We will sit down with our largest shareholders to make sure we understand their concerns,” he said.

Mr. Svanberg also said that the board had always “judged executive performance not on the price of oil or bottom-line profit but on measures that are clearly within management’s control.” And from that perspective, “the board has concluded that it has been an outstanding year,’’ he said. “The pay reflects this and it is consistent with our policy.”

A shareholder adviser, Tim Bush, called it “an unprecedented vote.’’

The 59 percent opposition was the highest dissenting vote yet cast against a large company in Britain under the country’s current remuneration laws, Mr. Bush, head of governance and analysis at PIRC, a London-based shareholder advisory group.

PIRC had recommended that shareholders oppose the pay package for Mr. Dudley and other BP executives as “excessive” and out of line with shareholder returns.

Since Mr. Dudley took over at BP after the in 2010 that killed 11 people and spilled millions of barrels of oil, he has made significant changes, including selling major assets. He is also credited with improving safety awareness at the London-based giant.

BP has been responding to lower oil prices by reducing costs. Besides cutting thousands of jobs, the company said recently that it would end its sponsorship of the Tate Museums in London.