LONDON — In a symbolic slap against high executive pay at a money-losing company, BP 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.