Wal-Mart heirs lost a combined of $5.7bn (£3.7bn, €5.1bn) from their net worth after the company's shares fell more than 4% in a single day in line with weak quarterly results.

The largest retailer in the US and the owner of Asda in the UK earlier reported a 0.1% decline in revenue to $114.8bn for the quarter ended in April, with earnings per share declining to $1.03 from $1.10. The company attributed the weak earnings to increased employee wages and currency fluctuations.

Following the results, Wal-Mart shares fell 4.4% to $76.43 on 19 May, marking their biggest single-day loss since April 2012. The plunge led to a significant decline in the combined fortune of Alice Walton, Jim Walton, Rob Walton and Christy Walton.

The four heirs have lost a total of $14bn so far in 2015, as shares plunged 11% during the period, according to the Bloomberg Billionaires Index.

Christy, the world's richest woman, currently has a net worth of $38.4bn, and she lost $3.4bn year-to-date in 2015, according to the index. Meanwhile, Jim lost $3.8bn so far in 2015 and is valued at $37bn. Rob has a net worth of $36bn at present, having lost $3.7bn in 2015. Alice, who has a net worth of $35.3bn, lost $3.7bn.

Despite a fall in gas prices, traditional retailers like Wal-Mart are struggling with slow sales growth, as consumers are increasingly shifting to online platforms such as Amazon.