Google did not announce a new share repurchase program as some analysts had speculated. Google said it bought 2 million of its shares in Q2 for $1.4 billion and has used up all of the funds the board has authorized for buybacks. "I'm not going to speculate about the potential for a future board decision," Alphabet CFO Ruth Porat said on the company's earnings conference call with analysts. Google had $78.4 billion in cash on its balance sheet as of June 30, up 12% from a year earlier. Google's spending on TAC became an issue after its Q1 earnings miss. TAC costs topped analysts expectations again in Q2, rising 18% from Q2 2015 to $3.975 billion, and rising 5% from Q1's $3.97 billion. Analysts polled by Thomson Reuters had modeled TAC at $3.9 billion. Google advertising revenue increased 19% from Q2 2015 to $19.1 billion, up from Q1's 16% year-over-year growth rate. "I do think as the shift to mobile search accelerates we are getting some scale benefits," Google CEO Sundar Pichai said on the earnings call.