The closed-end funds issue limited numbers of shares that trade on stock exchanges. Lately, the shares have been trading at premiums to the value of the assets in the fund portfolios. For example, Fiduciary/Claymore MLP Opportunity Fund ( FMO) sells at a 10% premium. So investors must pay about $1.10 for a dollar's worth of assets. To avoid the premiums, consider one of three open-end mutual funds launched in March by SteelPath Fund Advisors. SteelPath MLP Select 40 has a distribution yield of 6.6% and holds a cross-section of 40 MLPs. The fund aims to provide broad exposure to the industry. Investors seeking extra income can consider SteelPath MLP Income Fund, which yields 7.6% and focuses on large MLPs with high payouts. SteelPath MLP Alpha yields 6.6% and aims to hold undervalued securities that can deliver above-average total returns. SteelPath portfolio manager Gabriel Hammond particularly likes MLPs that can grow through construction or increased traffic. A favorite holding is Holly Energy Partners ( HEP), which operates pipelines that transport gasoline, jet fuel and heating oil in the Southwest. "The company can expand because demand in its territory is increasing," Hammond says. He also likes Inergy ( NRGY), which stores natural gas near New York City. Demand for the partnership is strong because storage facilities are in short supply in the Northeast, Hammond says.