Vanguard is set to roll out its newest exchange-traded funds.

The three new ETFs, which Vanguard submitted to the

Securities and Exchange Commission

last week, will track three of its foreign index funds: the

(VEURX) - Get Report

European Stock Index fund, the

(VPACX) - Get Report

Pacific Stock Index fund and the

(VEIEX) - Get Report

Emerging Markets Stock Index fund.

Unlike traditional open-end mutual funds, ETFs trade like stocks (or closed-end funds): They can be bought and sold throughout the trading day, sold short and bought on margin. Most charge lower annual expenses than even traditionally low-cost index funds (0.19% vs. 0.65%, according to Lipper), although there's a commission charge for each sale or purchase. So if you invest regularly, the periodic trading fees can add up to far more than an index fund's expense ratio. ETFs and index funds share the tax advantage of low-turnover investments.

Vanguard's ETFs are structured as new share classes of existing mutual funds.

Vanguard launched the first of its exchange-traded shares, Total Stock Market VIPERs, in May 2001. Its Extended Market VIPERs were launched in January 2002. The two ETFs combined have nearly $1.2 billion in assets.

Two of the three new VIPERs will be the first ETFs to track their respective indices -- the MSCI Europe and MSCI Pacific indices.