While most ETFs are index funds, some ETFs, particularly bond ETFs, do have active management. Actively managed ETFs are usually fully transparent, publishing their current securities portfolios on their websites daily. However, there are actively-managed ETFs that are not fully transparent. A transparent actively-managed ETF is at risk from arbitrage activities by people who might engage in front running since the daily portfolio reports can reveal the manager's trading strategy. Some actively managed equity ETFs address this problem by trading only weekly or monthly. Actively managed debt ETFs, which are less susceptible to front-running, trade more frequently.