Here is what you need to know.The Turkish lira continues its plunge. It hit an all-time low against the dollar on Friday after the European Central Bank said it was concerned about lenders' exposure to Turkey. ATurkish delegation in Washington had failed to prevent US sanctions over the arrest of the American pastor Andrew Brunson.The pound is still falling, too. It hit a fresh 11-month low against the dollar after data from the UK Office for National Statistics showed faster second-quarter gross-domestic-product growth but a manufacturing recession.Russia says US sanctions on banks or foreign currency dealings would be a declaration of 'economic war.' The US on Wednesday announced a new round of sanctions targeting Russia that pushed the ruble to two-year lows.Dropbox beat on 2nd-quarter earnings and announced a key executive was stepping down. Dropbox's chief operating officer, Dennis Woodside, long considered a key lieutenant to CEO Drew Houston, is leaving the company.Tesla's board reportedly may tell Elon Musk to recuse himself from talks about taking the company private. The board has told Musk he must consult different advisers as they seek counsel, CNBC reported.Tesla is now worth less than it was before Musk's $420 tweet. The stock closed down 5% Thursday at $352.45; it was worth $358 when Musk tweeted Tuesday about taking the company private.Bank of America asked 65 investors their biggest fearand the top response shows just how vulnerable markets are. A sharp loss of liquidity is now their biggest worry.Samsung unveils its Galaxy Note 9 and its answers to the Apple Watch and the HomePod. The company announced a slew of new products at an event in Brooklyn, New York, on Thursday.Inflation numbers are on deck. The July consumer-price index will be released at 8:30 a.m. ET.Global equity markets are in the red. Dow futures are down 0.4%, or 106 points. The 10-year yield is down 4 basis points at 2.895%.Join the conversation about this storyNOW WATCH: Everything wrong with the iPhone Click here to read full news..