NEW YORK - The nuns who are challenging Goldman Sachs' claim to be doing "God's work," by bringing a shareholder resolution challenging the bank's executive pay policies, are but the tip of an iceberg.

Thanks to a "say-on-pay" clause in last year's Dodd-Frank financial reform law, the pay of every senior executive of an American public company is now subject to a shareholder vote. So far in this spring's corporate annual meeting season, the management has lost such votes at four firms, the most prominent being Hewlett-Packard, a computing giant. Given the current mood for bashing bankers, it will be no surprise if there are similar results at Goldman Sachs and other financial institutions: All eyes will be on the first of the big banks to hold its vote, Citigroup, on April 21.

A new study by the Corporate Library, a research body, finds plenty for shareholders to vote against. It looks at those big companies that had, by March 20, reported their bosses' pay -- about a fifth of the S&P 500. Almost all reward them for long-term performance without considering whether similar firms are doing better. More than 75 percent of chief executives still have "golden parachute" severance deals worth at least twice their annual pay.

In the past year, things have gotten worse in three main respects, argues the Corporate Library. The difference between the chief executive's pay and that of other executives has grown. The dilution of other shareholders by awards of shares to executives has increased. And retirement benefits have become even more excessive.

It remains unclear how managers will respond to losing a vote on executive pay, as these votes are not binding. Occidental Petroleum, one of three firms that were defeated in the far smaller number of "say on pay" votes held last year, is rumored to be working on big changes in its pay policies, following criticism of the bounty enjoyed by its chief executive, Ray Irani.

However, says Robert McCormick of Glass Lewis, a firm that advises shareholders on how to vote, some managers are already trying to avert defeat by giving in to shareholder pressure before the issue goes to a vote. Disney, for example, issued a new proxy form (the document describing what shareholders will vote on) that cut the size of its bosses' golden parachutes, after investors grumbled.

Experience from Britain, which introduced say-on-pay in 2002, suggests that American shareholders can expect more improvements in the responsiveness of executives. Although few pay packages have been voted down by shareholders, that is because it is now routine for British executives to consult investors on pay policy long before it goes to a vote.

Colin Melvin of Hermes Equity Ownership Services, which advises institutional investors on such matters, says the overall result has been much better communication between managers and shareholders. In contrast, he says, American bosses still seem disinclined to have such a dialogue.

That is certainly true of this year's other hot topic for American shareholder voting: resolutions pressing companies to disclose their political donations. Such resolutions have proliferated since a Supreme Court decision last year to overturn restrictions on corporate political spending. Citigroup's bosses, for example, will oppose a motion from some shareholders calling on them to disclose the bank's donations.

Although the signs of progress are clearer in Britain, institutional shareholders there are coming under pressure to do more to hold company bosses to account. Last month, FairPensions, a lobby group, issued a report calling for a tightening of the fiduciary responsibility law for pension funds, insurers and other big investors who manage people's money. The group wants to force these to play a fuller role in corporate governance and to disclose how they vote their shares. A similar change is said to be under discussion in America, including within the Securities and Exchange Commission.

Further reforms would be welcomed by activist investors such as Nelson Peltz, who has a long record of battling entrenched managers at firms as varied as Heinz and Tiffany.

Speaking to America's Council of Institutional Investors this week, Peltz said that say-on-pay and other recent improvements to corporate governance will help shareholders like him take on previously "untouchable" corporate giants. Martin Lipton, a lawyer who has often defended managers against shareholder attacks, worries that activists like Peltz would be able to use the new rules to embarrass big institutional investors into backing their campaigns.