Walmart's $9 billion deal to sell its UK supermarkets is dead

The United Kingdom's Competition and Markets Authority said on Thursday that it has blocked Wal-Mart's proposed sale of its British supermarket chain Asda to rival Sainsbury's.

The deal valued Asda at £7.3 billion ($9.4 billion), and would have created a mega retailer with 2,800 stores and combined annual sales of roughly £51 billion ($66 billion).

The antitrust watchdog ruled that the deal would be bad for British shoppers as it could lead to higher prices, lower quality goods and a poorer shopping experience in general.

"It's our responsibility to protect the millions of people who shop at Sainsbury's and Asda every week," said Stuart McIntosh, who led the CMA investigation. "We have concluded that there is no effective way of addressing our concerns, other than to block the merger."

This is a developing story.