Walmart stock has dropped more than a third since it started trading in earnest on Monday.
The stock’s price dropped about 13% in one day, the biggest daily decline since mid-September, as it tumbled on concerns that the retailer could lose customers if a merger between Walmart and Aldi falls through.
It also has been hit by the fallout from the death of a longtime executive.
On Friday, the company announced that former chief executive Andrew Puzder had been diagnosed with a terminal cancer.
Walmart announced Monday that it had hired Michael Nesbitt, a former senior adviser to the White House, to serve as its new chief operating officer.
The company also has said it plans to hire three additional people.
The news came just days after Nesbit was named Walmart’s new CEO, replacing CEO Andrew Mason.
The company’s shares were down almost 6% in premarket trading Monday, before they jumped almost 12% to $11.95.
The Dow Jones Industrial Average ended down 7.8% and the S&P 500 rose 0.4%.
The retail giant has also had some trouble attracting shoppers and keeping them.
In its first quarter, the retailer’s profit dropped 8.9%, while net sales fell 12.6%.
It said it would cut 1,500 jobs as it sought to cut costs and improve its profitability.
The retailer has struggled to sell its merchandise.
The stock has slumped almost 15% this year.
In February, it reported a loss of $9.5 billion.
Last month, the stock tumbled as it faced increasing scrutiny from Congress over its business practices.
The Senate is considering a bill that would require it to disclose how much its workers are paid and where the money is going.