Google and Yahoo has agreed to postpone a planned online advertising deal while US regulators consider its implications.
This is the second time they've delayed a deal initially signed in June.
"When we announced our advertising agreement with Yahoo! in June we agreed to delay its implementation until October to give regulators time to look at the details," reads a Google statement.
"As we are still in conversation with the Department of Justice we have agreed to a brief delay in implementing the agreement while those discussions continue."
The deal was announced while Microsoft was attempting to purchase Yahoo earlier this year and helped Yahoo stave off the Microsoft advances.
Protagonists argue that the tie-up would create a de facto monopoly in the online advertising space and lock out competitors.
In terms of the agreement, Google ads would be posted alongside Yahoo search results.