Amazon posted sales numbers that grew by $15 billion year over year when it reported second-quarter earnings Thursday. Its peers in retail and cloud services don't come anywhere near that level of growth.

Amazon reported sales of $52.9 billion for the second quarter, up 39 percent from the year-ago period when it saw $38 billion. The bulk of that comes from North American sales, consisting of retail sales and subscription fees for the company's Prime memberships. Cloud revenue increasingly drives revenue growth, growing by 49 percent in the second quarter.

The numbers trounce Amazon's industry competitors in retail:

Retail rival Walmart grew sales by $5 billion year over year in the April quarter, the most recent quarter for which data is available. That's a growth rate of 4.4 percent year-over-year.

year over year in the April quarter, the most recent quarter for which data is available. That's a growth rate of 4.4 percent year-over-year. Brick-and-mortar retailer Target increased sales by just $764 million for the April quarter. The company's total sales for the period rang in at 16.8 billion — just above Amazon's net new sales.

Tech competitors get closer to Amazon's staggering pace:

Apple, Amazon's main competition in the race to a $1 trillion market value, grew revenue by 16.6 percent, or $8.7 billion , in the March quarter. The iPhone maker reports quarterly earnings next week.

, in the March quarter. The iPhone maker reports quarterly earnings next week. Cloud rivals Google and Microsoft each posted just under $7 billion of net new sales for the June quarter.

Amazon's been growing sales at impressive rates for four consecutive quarters, too, reporting year-over-year increases of 42.9 percent in the previous quarter, 38.2 percent in the December 2017 quarter, and 33.7 percent in the September quarter.

The company guided toward third-quarter revenue between $54 billion and $57.5 billion — below Wall Street estimates, but still a year-over-year upside of 23 to 31 percent.

"The secular tailwinds on both the consumer and enterprise fronts are massive for Bezos & Co. going forward," GBH Insights analyst Dan Ives wrote in a note after the report. "The profitability trajectory appears to be accelerating quicker than expected, which, given the leverage in the Amazon model, is a 'potential game changer' that could translate into further multiple expansion."

—CNBC's Ariel Shapiro contributed to this report.