"The team ... is putting even more energy around making sure we get great productivity around our various fixed and variable investments," Chief Financial Officer Tom Szkutak told reporters on a conference call.
This was a shift in tone for Amazon, which typically refuses to disclose more than the most basic details, including how many members belong to its $99-a-year Prime program or if its wide-ranging investments are paying off.
Chief Executive Jeff Bezos has deflected criticism of his spending by emphasizing that he takes a much longer view than most investors. Late last year, he boasted that he spends just six hours a year on investor relations.
Read MoreGoogle misses on earnings, blames strong dollar
But Amazon shares dropped by more than 20 percent last year as investors grew weary of its spending on film and television productions, grocery delivery and consumer devices. Amazon also has fallen short of estimates in five of the last eight quarters.
The additional information shared during Amazon's fourth-quarter results as well as its emphasis on becoming more efficient signaled a new willingness by Amazon executives to listen to investors as well.
"This quarter, Amazon flexed its muscles and said this is what we can do when we focus on profits," said Rob Plaza, senior equity analyst for Key Private Bank. "If they could deliver that upper teens, low 20s revenue growth and be able to deliver profits on top of that, the stock is going to respond."
The change is unlikely to be dramatic. When asked whether this quarter marked a permanent shift in Amazon's relationship with Wall Street, Plaza laughed: "I wouldn't be chasing the stock here based on that."
Still, the shift is a good sign for investors, who have been clamoring for Amazon to disclose more about its fastest-growing and likely most profitable division that some analysts say accounts for 4 percent of total sales.
The change seemed unlikely until AWS made up 10 percent of Amazon's net sales, the threshold at which U.S. securities regulators require disclosure.