A master limited partnership is a limited partnership that is publicly traded. The master limited partnership's distinctive feature is an exception from the general tax treatment of publicly traded partnerships. In general, publicly traded partnerships are taxed as corporations and do not receive the pass through tax treatment that other partnerships receive because of Internal Revenue Code Section 7704. However, the Section has an exception that provides that if at least 90% of the partnership's gross income constitutes "qualified income" under that code section, the partnership will still be taxed as a partnership. Qualified income primarily includes income from exploration, development, mining, production, processing, refining or transportation of mineral or natural resources. Thus, most master limited partnerships tend to be concentrated in the energy and natural resource sectors.