Opinion: Amazon profits, Alphabet stock repurchase show effects of new CFOs Two of tech’s maverick companies, Amazon.com Inc. and Alphabet Inc. (formerly known as Google), made grown-up moves Thursday, and reaped rewards from Wall Street. Alphabet GOOGL, +5.61% GOOGL, +5.61% announced its first-ever stock buyback plan, with plans to spend more than $5 billion buying back its own stock, beginning in the fourth quarter. Wall Street has been agitating for some time about Google’s growing cash pile, which soared to $73 billion at the end of September. Alphabet’s new chief financial officer Ruth Porat, who joined the Internet search and advertising giant from Morgan Stanley, appears to be focusing on investor returns more than Google’s founders did. For its part, Amazon AMZN, +6.23% AMZN, +6.23% AMZN, +6.23% also is showing more financial discipline, announcing a surprise profit for the second consecutive quarter even as it continues to invest in new products, along with its vast and growing infrastructure and delivery systems. The e-commerce giant also has a new chief financial officer, Brian Olsavsky, and he surprised investors with a forecast for an operating profit for the busy holiday quarter, with a guidance range that included a profit on both sides. Amazon also is predicting revenue in the fourth quarter could soar as much as 25%. Alphabet and Amazon have long been known for free-spending ways, throwing caution to the wind in an effort to grow fast. But the new CFOs at these companies appear to be ceding a bit to investor demands for more focus on stock prices and happy investors than writing checks. Doug Anmuth, a J.P. Morgan analyst, asked during the conference call what he said is the most popular question among investors, which is whether or not Amazon will “flip back to its heavier spending ways of 2014 and earlier,” as it continued to invest in its growing infrastructure and fulfillment centers and reported quarterly operating losses, despite strong revenue growth. Olsavsky said that the company has continued to make big investments in product innovation and infrastructure in the quarter, which also saw a huge profit boost in its AWS cloud hosting business. But he noted, “We will continue to work on costs,” adding that “cost reductions” will be a constant presence at the company. Google sounded a similar tune. While noting continued investment in capital expenditures and a 16% year-over-year gain in employees, Porat also preached a focus on profitability by controlling costs. Investors loved the fact that both companies are becoming serious about returns to shareholders. Amazon’s shares soared more than 10% in after-hours trading, while Alphabet jumped more than 9%. While investors enjoy the euphoria now, it’s worth remembering that the early stages of corporate adulthood are usually followed with a slowing down of that once torrid growth rate. The leaders of both of these companies know, however, that just as an actor’s prime is fleeting, so too can be the life of a tech juggernaut. More from MarketWatch