SYDNEY, April 19 (Reuters) - A consortium backed by U.S. private equity giant KKR & Co KKR.N offered A$6.15 billion ($4.65 billion) cash for Australian lottery operator Tatts Group Ltd TTS.AX , threatening an agreed merger with Tabcorp Holdings Ltd TAH.AX , two sources familiar with the situation said on Wednesday.
The sources, who were not authorised to speak publicly, told Reuters a letter offering A$4.21 a share had been sent to the Tatts board on Tuesday evening.
Tatts in October agreed to accept a cash-and-scrip proposal from betting group Tabcorp to form an Australian gambling powerhouse. shares closed at A$4.35 a share on Tuesday. ($1 = 1.3226 Australian dollars)