A behind-the-scenes account of J.P. Morgan's huge losses provides new details about the drama inside the bank as executives sought to understand the scope of the disaster and decide what to do about it.

At least 20 closely held U.S. start-ups backed by venture capital are now valued at $1 billion or more, Pinterest and Evernote among them. During the frothy days of the 1990s dot-com bubble, there were just 18 such start-ups valued at $1 billion or more.

Alexis Tsipras, head of Greece's radical left party, said in an interview with the Journal that there is little chance Europe will cut off funding to the country and if it does, Greece will repudiate its debts.