Porat joined Google in May after serving as Morgan Stanley's chief financial officer for five years. Analysts and investors hoped she would help rein in costs from non-profitable projects such as those from the Google X lab, which has experimented with Google Glass and the self-driving car.
Google's shares started rising after the company reported higher-than-expected earnings for the first time in six quarters.
Also boosting the stock were Porat's comments in a prepared statement that said the company was focused on developing "big new opportunities" while doing so "with great care regarding resource allocation."
Before the call, shares were up roughly 7 percent. In the course of the call the shares rose roughly 12 percent. Late in the day shares were up a little over 11 percent, at $671, after closing at $601.78 on the Nasdaq.
That would represent an all-time high for the stock in regular trading if it closes at that level on Friday, adding roughly $40 billion to its market value.
On the analyst call, Porat continually emphasized operating costs that were growing more slowly and declining expenses that reflected increased discipline in the managing of expenses.