Majority voting policies, executive compensation and poison pills typically top the agendas of activist investors these days. Yet another perennial sore point with shareholders continues to lurk quietly beneath the radar, too: dual-class stock structures.

Common perception is that dual-class structures are the domain of a few, family-owned businesses such as Ford Motor Co. or the New York Times. Actually, the numbers are larger and stubbornly steady: Currently 10.4 percent of the nearly 2,000 companies tracked by Institutional Shareholder Services have a dual-class structure, compared with 11.5 percent at the beginning of 2000. On the Standard & Poor 500, 8.7 percent of listees report a dual-class stock, compared to 8.2 percent at the start of the decade.