NEW YORK (Reuters Breakingviews) - Jeff Bezos has some solid timing. The founder and chief executive of Amazon.com is handing over the CEO role to Andy Jassy, head of the cloud division AWS, after a fortuitously good year at the $1.7 trillion retail giant. The new boss will face a different, more challenging normal that includes regulatory scrutiny. First the results: Amazon said Tuesday that fourth-quarter revenue rose 44% year-over-year to $126 billion. That’s the first time the company topped $100 billion of sales in a quarter helped by delivering items to customer’s doorsteps during the pandemic and, of course, the holidays. ADVERTISEMENT That’s the good news. The rest harkens some major challenges for Jassy. Operating expenses ballooned 42% in part because costs associated with worldwide shipping rose about two-thirds. The vaccine rollout will coincide with choice, which could make life harder for Amazon. The company is forecasting sales volume to drop by a quarter in this period compared to three months ending December. The hurdles may partly be why Jassy is now leading the company. AWS is one of Amazon’s jewels. Growth slowed a tad in the fourth quarter to 28%, but the division has much higher margins than Amazon’s other units, booking more than half of its operating profit despite accounting for just 12% of total sales. ADVERTISEMENT And yet Amazon’s success is precisely what will make Washington continue its pursuit of the retail giant. On the same day as earnings, Amazon agreed to pay more than $60 million to the Federal Trade Commission to settle charges it withheld some tips from drivers. Time away from the corner office will give Bezos the opportunity to focus on his other projects including the Bezos Earth Fund and the Washington Post. He will likely continue to have a guiding hand, too, and perhaps will find himself in the Beltway hot seat. Still, the company’s forward enterprise value-to-sales figure is hovering near its high, hit earlier this year. As Bezos steps aside, Amazon is staring at the end of living high on the hog. BREAKINGVIEWS Reuters Breakingviews is the world"s leading source of agenda-setting financial insight. As the Reuters brand for financial commentary, we dissect the big business and economic stories as they break around the world every day. A global team of about 30 correspondents in New York, London, Hong Kong and other major cities provides expert analysis in real time. Sign up for a free trial of our full service at https://www.breakingviews.com/trial and follow us on Twitter @Breakingviews and at www.breakingviews.com. All opinions expressed are those of the authors.