Influential investor advisory firm Institutional Shareholder Services has thrown its weight behind a shareholder proposal to require Apple to disclose a succession plan for chief executive Steve Jobs. The proposal backed by ISS, a proxy voting service, was submitted by the Central Laborers' Pension Fund. Last month, Apple CEO Jobs stepped away from the company on medical leave for an undisclosed condition. Chief operating officer Tim Cook is now overseeing day-to-day operations. "ISS believes that shareholders would benefit by having a report on the company's succession plans disclosed annually," ISS said, according to a release from the Laborers' International Union of North America. "Such a report would enable shareholders to judge the board on its readiness and willingness to meet the demands of succession planning based on the circumstances at that time."