Last quarter, Amazon.com Inc. hinted that spending on investments such as data centers and warehouses would rise in 2019. The magnitude of those outlays is one of the biggest questions investors have ahead of Amazon’s first-quarter earnings on Thursday afternoon.

The answer will help determine how profitable the world’s biggest Internet retailer will be, and is a yardstick that investors have become increasingly fixated on as Amazon pushes deeper into more lucrative businesses such as cloud computing and advertising.

"Investors are once again focused on investment spending and corresponding margin outlook," Robert W. Baird analyst Colin Sebastian wrote in a research note.

Amazon (AMZN) has historically returned relatively little in the way of profits, instead opting to aggressively invest in new markets and emerging technologies. First-quarter net income is expected to total about $2.3 billion on revenue of $59.7 billion, according to the averages of analyst estimates compiled by Bloomberg. Amazon Web Services is expected to contribute $7.67 billion in sales, up 41 percent from the same period a year ago, according to the average of four estimates.

Amazon has gained 42 percent since the market bottomed on Christmas Eve, adding almost $280 billion in market value. An upside surprise in the earnings report could boost the company’s valuation above $1 trillion, a distinction it achieved briefly last year. The options market is implying about a 5 percent move in the stock, which would put it about $15 billion shy of the 13-figure mark.

The rapid growth of AWS and advertising sales should fuel operating margin expansion throughout the year even if Amazon ratchets up spending, Stifel analyst Scott Devitt said. Those businesses will account for about 18 percent of Amazon’s revenue in the first quarter, up from about 15 percent a year ago, he estimates.