In June, the two companies announced plans for a 10-year deal, in which Yahoo will allow Google to put search advertising next to its search listings, and gave anti-trust authorities 100 days to look at the arrangement before it came into effect.
Yahoo expects to generate between $250m (£126m) and $450m (£227m) from the venture within the first three years of operation.
However, the US Justice Department is still looking into the agreement, amid criticism from Microsoft that it would lead to Google and Yahoo controlling nearly 90% of the North American search ad market.
There are concerns that the deal would give Google too much power and so the antitrust investigation was launched.
In an interview with Bloomberg television, Google chief executive Eric Schmidt said: "We are going to move forward. We are in the process of talking to the government. They've not indicated one way or the other how they're dealing with us."