Amazon is the figurehead for the supply chain revolution that has caused a boom in industrial real estate, and it is still growing its influence.

In its annual 10-K filing with the Securities and Exchange Commission, Amazon added transportation and logistics companies to its list of competition in 2018, CNBC reports. It is the first time Amazon has named shipping and logistics as a moneymaking element of its company.

For many of the products listed on its site, Amazon acts as a go-between for merchants of consumer goods and shipping companies that take those goods to consumers' doors. Though its entries into the seller arena have grabbed headlines, it has increased the use of its own services in shipping and relied less exclusively on partners such as FedEx, UPS and the United States Postal Service, according to CNBC.

Like much of its other business, Amazon's strategy of entry into the shipping market seems to be undercutting the prices of its competitors — in the case of a pilot program last year in Los Angeles, as low as half of what FedEx charged merchants, CNBC reports.

In a recent call with analysts, Amazon executives announced a plan to increase investment back into the company. Amazon's 10-K filing could provide some insight into where that investment will go — perhaps into further building its empire of increasingly massive distribution centers.