D annine Avara is an American billionaire heiress and one of the four children of the late Dan Duncan, the founder of the massive pipeline company Enterprise Products Partners. Dan Duncan was a legendary self-made Texas energy tycoon who built his company from a two-man operation into one of the largest and most successful midstream energy companies in North America, with a vast network of pipelines and storage facilities.

Upon her father's death in 2010, Dannine and her three siblings, Randa Duncan Williams, Milane Frantz, and Scott Duncan, inherited his multi-billion dollar fortune. The family's wealth is held in trusts that own a massive stake in the publicly traded Enterprise Products Partners. While her sister Randa serves as the non-executive chairman of the company, Dannine is not involved in its day-to-day operations. Her immense wealth is derived from her inherited stake in the enduring pipeline empire her father created.