EBay has signed a definitive agreement to sell its Skype communications unit to an investor group led by Silver Lake. Under the terms of the deal, eBay will receive approximately $1.9 billion in cash, a note from the buyer group for $125 million. It will retain approximately a 35% equity investment in Skype. EBay said the deal values Skype at $2.75 billion. The deal is expected to close in the fourth quarter.