An Exchange-traded notes (ETN) is a type of unsecured debt security that tracks an underlying index of securities such as the S&P 500 and trades on a major exchange like a stock. In addition, in contrast to exchange-traded funds (ETFs), which are required to be fully transparent about their holdings, ETNs do not have to disclose holdings on a daily basis.Exchange-traded notes (ETNs) are unsecured debt securities that track an underlying index of securities and trade on a major exchange like a stock. ETNs are issued by the issuer, and they can be redeemed at any time by the investor during regular trading hours.ETNs are unsecured debt securities that track an underlying index of securities and trade on a major exchange like a stock. ETNs are similar to exchange-traded funds because they allow you to invest in assets, such as commodities or currencies, without buying the individual assets.