Through their family foundation, the couple pledged USD 1 million in 2014 to the University of Michigan to develop a start-up accelerator.
Ullal became president and CEO of Arista Networks, a company that has emerged as one of Silicon Valley's most valuable networking firms. Forbes said Ullal "is one of America's wealthiest female executives".
"She took slightly more than an engineering team doing some good technology and turned it into the thriving network switch company it is today," Forbes quoted Arista co-founder David Cheriton as saying.
Born in London and raised in New Delhi, Ullal has donated some shares to a family foundation created in honour of her sister, who died of lung cancer, Forbes said. The first ever list of the nation's top 50 most successful, self-made women as measured by their net worths includes entrepreneurs, CEOs, entertainers, designers and an author.
Elizabeth Holmes, who dropped out of Stanford to launch blood testing firm Theranos in 2003, tops the list with a net worth of USD 4.5 billion. At 31, she is also the world's youngest female billionaire.
Other notables who made the cut include Eren Ozmen, who is chairman of Sierra Nevada, the biggest female-owned federal contractor in the US, creator of American Girl dolls Pleasant Rowland, prolific novelist Nora Roberts, and Martine Rothblatt, a transgender woman who founded and runs biotech firm United Therapeutics. The list also includes Hewlett-Packard CEO Meg Whitman ranked 10, singer Madonna (28), designer Vera Wang (34) and Yahoo CEO Marissa Mayer (36).