Bitcoin and Ethereum prices slid on Tuesday, July 28, ahead of the U.S. Federal Reserve's two-day policy meeting. Bitcoin opened 2.5% lower at $63,706.66, and Ethereum opened 3.2% lower at $1,890.67. The CME Group's FedWatch tool indicates a 35.8% chance of a Fed rate hike following the meeting, up from 25.7% last week, with some analysts calling it the hardest Fed meeting to predict in years.