XMPT is a fund of closed-end funds that provides broad exposure to municipal bonds that are exempt from US federal tax exposure through the lens of US-listed closed end funds (CEFs). The ETFs underlying funds fall into four categories depending on whether they are leveraged and/or high-yield. A committee maintains a list of CEFs that are divided into sectors, based on the CEFs stated investment style. After review, the committee selects CEFs based on their overall standards for risk and sound business practice. Weighting is based on total net assets of the CEFs, adjusted for each CEFs average discount for the previous 90 days. Effectively, overweighting CEFs trading at discount. Take note that CEFs lack the arbitrage mechanism baked into ETFs, so they often trade at premiums or discounts to fair value. The index is reconstituted annually and rebalanced quarterly.