In the first "say when" vote at an S&P 500 issuer, Monsanto investors overwhelmingly defied management's triennial recommendation and voted for an annual advisory vote on executive compensation at the agricultural company's annual meeting today. 

There was 62.2 percent investor support for annual, a 35.9 percent vote for triennial, 1.4 percent support for biennial, and 0.5 percent abstentions, according to a company filing.  These results do not include discretionary broker votes, which cannot be cast for management during these frequency votes.

Monsanto's board responded quickly to the vote, which was non-binding. "In accordance  with the results of this vote, the Board of Directors determined to implement an annual advisory vote on executive compensation," the company said in a press release. 

"The Monsanto vote of 62 percent for annual votes on Say on Pay is the shot that will be heard around America's boardrooms," said Tim Smith, a senior vice president at Walden Asset Management and an active proponent of annual votes. "Despite the board's recommendation for a triennial pattern of votes, investors voted thoughtfully and actively for annual accountability on pay, giving investors regular opportunities for feedback on executive compensation."

Today's vote on pay vote frequency was especially significant because Monsanto is a widely held company with a significant number of institutional investors and no large inside share block. If investors at other large-cap firms follow suit in the next few weeks, it appears likely that these results may sway boards at companies with late spring meetings to recommend annual votes. More results like today's vote at Monsanto may prompt undecided institutions to back annual votes as well. 

Investors at Johnson Controls, Costco Wholesale, and Visa also will express their views on pay vote frequency at annual meetings this week.

Under the Dodd-Frank Act, U.S. companies must hold a "say on pay" vote and a "say when" frequency vote at their first annual meeting after Jan. 21, except for smaller reporting companies, which will get a two-year exemption from these mandates. So far, a majority of issuers with early meeting dates have recommended a triennial vote, but some governance experts expect to see more annual recommendations as the season progresses.