7-Eleven in $2bn bid to buy Casey's

The biggest convenience store chain in the US, 7-Eleven, has made a $2 billion (£1.3bn) offer to buy smaller rival Casey's.

It is thought the approach could spark a bidding war as Canadian retailer, Alimentation Couche-Tard, has previously made two bids for Casey's.

7-Eleven operates more than 7,000 outlets in the US and Canada, while Casey's has about 1,500 stores.