OKLAHOMA CITY -- A legal loophole could leave investors at Sunrise Senior Living ( SRZ) in the dark. When Sunrise hosts its annual meeting on Tuesday in McLean, Va., many shareholders may not realize it is even taking place. Moreover, those who do manage to show up could end up powerless to take any action -- unless they bring certain documents necessary to approve corporate governance changes. How did Sunrise's shareholders end up in such a predicament? The problem starts with the fact that Sunrise -- working on a restatement tied to a probe of past options accounting -- has fallen behind in filing audited financial statements. Without filing audited financials, experts say, a company can't mail out the proxy materials that typically put board elections and other governance issues before shareholders for a vote. Ironically, Sunrise's very failure to keep its books current could end up insulating its board -- one that has failed to catch serious accounting problems, among other shortcomings -- from any accountability to the company's owners. By failing to play by the rules, critics say, company leaders have gained a valuable edge on ordinary shareholders eager for reform. Even the nation's leading proxy advisory firms have struggled to help investors. In a recent note to clients, heavyweight Institutional Shareholder Services warned shareholders that they "must take special steps in order to attend this meeting in person or have a proxy generated" on their own. Meanwhile, without a definitive proxy statement, ISS said that it is "not in a position to deliver a research analysis or vote recommendations for the meeting."