One of the growing trends in Amazon's business is its fattening profit margins.



In the first quarter, it had $1.6 billion in net income — more than double from last year and only the second quarter in company history to top $1 billion in profit.

That change is partly driven by the growth in Amazon's gross profit — the money left after taking out fixed costs for things such as inventory, digital contents, storage and shipping.

To illustrate this change, Morgan Stanley compared the year-over-year dollar growth in Amazon's first-quarter gross profit with what the top five retailers are collectively expected to book.

The difference is staggering: Amazon grew its gross profit by $7 billion during the first quarter. That's nearly five times as much gross profit growth as Morgan Stanley expects for the top five retailers combined.