When the big-name stars of corporate America convene this spring for the rigorously scripted dramas known as annual shareholder meetings, the dwindling cast of bit players could be even smaller than in years past.

That’s because the New York Stock Exchange is amending a rule governing how shares held in street name are voted at the meetings. “Street name” refers to stock held by a broker even though the broker’s clients are the actual owners.

In the past, brokers who held the shares had to ask clients how to vote them at stockholder meetings. If they didn’t get instructions, brokers could vote them as they pleased. They typically voted in line with the wishes of management, says Robert K. Morris, a Reed Smith securities-law expert.

This change to the NYSE rules affects votes on only “non-routine” matters: changes in stock compensation plans, shareholder proposals and, most important, the election of directors. On these matters, brokers can vote shares only if they receive instructions from clients.

Because many shareholders fail to provide instructions, some are concerned that turnout at the meetings – poor even by the standards of political elections – will decline even more.

Experts aren’t that worried about turnout dropping so much that companies are forced to reschedule meetings because they lack a quorum. The bigger worry is that the change could make it easier for organized shareholders to influence the outcome of elections – for better or worse, depending on whether you’re management or a dissatisfied investor.

Michelle Lowry, who teaches finance at Penn State’s Smeal College of Business, says broker-held shares accounted for about 16 percent of all shares eligible to vote in 2008. If rules for voting broker-held shares had been made a few years ago, “there’s evidence in some elections it may have made a difference,” Lowry said.

Electing corporate board members isn’t the highest form of democracy.

Candidates are typically nominated by a company’s current directors and run unopposed. Like voters in political elections, it’s hard enough getting investors to the polls, much less convincing them to study the voluminous material that the Securities and Exchange Commission requires companies to provide to shareholders in advance of a vote.

Some believe that declining shareholder turnout has been fueled in part by SEC initiatives to reduce the significant costs of providing those documents. The per-shareholder costs for printed materials can be $2 to $6, and postage can add another $2.50 to $3.50 per shareholder, says Robert Folinus, a vice president of BNY Mellon Shareowner Services.

To reduce that burden, the SEC for the past two years has given companies the option of sending stockholders a one-page letter informing them that proxy materials are available, either online or by calling for hard copies.

More than 1,300 companies exercised the lower-cost option last year and saved an estimated $239 million, according to Broadridge Financial Solutions, whose services include helping companies with shareholder communications. But Broadridge also found that fewer investors voted when they didn’t get the materials the old-fashioned way.

Prohibiting brokers from voting shares for which they don’t get instructions likely won’t change the outcome of elections at companies that use plurality voting to elect directors. Management-backed candidates still have to get just one more vote than their opponents – if they even have any.

But it could cause problems at companies that require director candidates to get a majority of votes cast. If enough investors didn’t give voting instructions, activist investors such as pension or hedge funds could organize enough other shareholders to determine the outcome of an election.

Folinus said that is more likely to happen at companies that have a large percentage of individual investors. Small companies often but not always fit that bill, he says.

Meanwhile, the SEC is changing the rules on the one-page notice option, allowing companies to include additional information about the importance of voting without telling investors how to vote.

Some have urged the SEC to allow companies to distribute a voting card with the one-page notice. They argue that making investors download the information from the computers or call for the proxy material discourages shareholders from voting because it adds an extra step to the process.

Morris says that would make it possible for investors to vote without educating themselves by reading the material. But few individual investors are equipped to understand – much less take the time to read – the bulky reports.

“Very few people except us proxy geeks actually read proxy statements,” Folinus said.

The SEC provides information online on how proxy voting works and why it’s important at www.sec.gov/spotlight/proxymatters.shtml.