This is CNBC's Morning Squawk newsletter. Subscribe here to receive future editions in your inbox. Good morning, and happy Tax Day. As of last week, the average tax refund this year is more than 10% higher than the same time a year ago, according to IRS data. S&P 500 futures are little changed this morning after the index posted its ninth positive session in 10 yesterday. Here are five key things investors need to know to start the trading day: All three major indexes climbed for a second