$2 trillion! Friday's sell-off was an all-time record; UK stripped of top credit rating; and more news

S&P downgraded the UK's sovereign debt rating from AAA to AA. "In our opinion, this outcome is a seminal event, and will lead to a less predictable, stable, and effective policy framework in the UK," the ratings agency said. It's a two-notch drop from perfect for the UK, and S&P's outlook is negative.

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Brexit Blues: Equities markets fell sharply again Monday, though major US indexes closed off session lows. But Friday was one for the books: global stock markets collectively lost more than $2 trillion, the worst trading day ever in dollar terms. No other event (see chart below) had ever caused such investor malaise, though on a percentage basis there have been darker days.

Volkswagen's US bill for the emissions scandal has ballooned to $15 billion —  $5 billion more than reported last week, Bloomberg reports. In addition to $10.3 billion that will make car owners whole and also top them off by as much as $10,000 each, the proposed settlement includes a $2.7 billion EPA fine and $2 billion to develop clean-emissions technology. This tally "brings VW closer to the $18.3 billion it has set aside to cover the costs of the scandal."

Clash of the Titans: Kroger (the nation's biggest grocery chain by revenue) and Visa (which owns more than half the card market) are fighting how debit cards are processed. Kroger insists customers use PINs instead of a signature, which allows them to route the transaction to "networks other than Visa," The Wall Street Journal reports, avoiding some processing charges. Big bucks are at stake: Kroger processed $29 billion in Visa debit-card transactions last year. WalMart sued Visa over this issue last month.

Pepsi is bringing back aspartame-sweetened diet soda. It's said to be a limited run, and that the aspartame-free version of Diet Pepsi unveiled a year ago "will remain the marketer's flagship diet cola," AdAge reports. But the resurrection does come amid flagging diet soda sales and as part of "broader overhaul" that will also rename Pepsi Max to Pepsi Zero Calorie (the better to compare and contrast to Coke Zero).   

Florida's Stonegate Bank has become the first US institution to issue MasterCards that can be used at ATMS in Cuba. The local bank chain has issued only 500, "mainly to Cuban Americans" who do business on the island nation, Reuters reports. Did Stonegate just manage to make it through an arduous process first, cleverly navigating the choppy early waters of normalization? Evidently not. "To date no other U.S. bank has approached us or expressed an interest," a Cuban banking official said.

Cover Art: The Queen Elizabeth Tower (Big Ben) is reflected in a puddle as a cyclist rides by in London, June 27, 2016. Britain began preparations to leave the European Union but said it would not be rushed into a quick exit, as markets plunged in the wake of a seismic referendum despite attempts to calm jitters.