Kevin Horner examines the S&P 500's (SPX) grinding higher pattern and notes that a close below the 20-day moving average of 5,925 would be a significant departure from the trend. He also highlights Caterpillar (CAT) as it attempts to re-grab the 200-day moving average of 350.8, a key resistance level. Horner also mentions Uber (UBER) which has broken out of a $20 range and may be due for a retest of its recent high.