Block says it is laying off more than 4,000 of its 10,000+ employees; XYZ jumps 19%+ in extended trading (Annie Palmer/CNBC)

Annie Palmer / CNBC: Block says it is laying off more than 4,000 of its 10,000+ employees; XYZ jumps 19%+ in extended trading   —  Block said Thursday it's laying off more than 4,000 employees, or about half of its headcount.  The stock skyrocketed more than 24% in extended trading.