The United States Postal Service denied J.C. Penney Co. Inc. (JCP) CEO Marvin Ellison's assertion made earlier this week, which was first reported by TheStreet, that it would be the one to hold back future e-commerce growth.

A USPS spokesman said in an email to TheStreet that the agency's "unrivaled network and infrastructure" will "enable" and "facilitate" e-commerce's "future growth," pointing out that its workers delivered 154 billion pieces of mail to the U.S. in 2016.

"The Postal Service continually adapts to a dynamic marketplace," the spokesman said on Friday. "We operate an extensive and integrated retail, transportation, processing and delivery network to serve residential and commercial customers."

At a Piper Jaffray conference on Wednesday, Ellison said e-commerce companies' like Amazon Inc. (AMZN)  biggest challenge ahead is the USPS in particular, as it delivers more packages to homes in the U.S. than any other shipper.

J.C. Penney's Marvin Ellison.
J.C. Penney's Marvin Ellison.

"Fulfillment costs are increasing dramatically because we have UPS (UPS) , FedEx (FDX) and USPS as the three main entities to ship and fulfill orders and they're not increasing capacity to deliver at the same rate e-commerce is growing," Ellison said.

He said this will cause a supply and demand issue "that's going to be apparent here pretty soon."

J.C. Penney's shares fell 3.4% to $4.85 at Monday's close.

Visit here for the latest business headlines.

Editors' pick: Originally published June 16.

More from Stocks

Dow Rallies on Signs of a Thaw in U.S. and China Trade Battle, Nasdaq Slumps

Dow Rallies on Signs of a Thaw in U.S. and China Trade Battle, Nasdaq Slumps

DOJ Isn't the Only One: Audi, BMW, Mercedes Are Gunning for Tesla Too

DOJ Isn't the Only One: Audi, BMW, Mercedes Are Gunning for Tesla Too

My New Age Beverages Trade Is Killing It (Glad I Didn't Listen to the Bears!)

My New Age Beverages Trade Is Killing It (Glad I Didn't Listen to the Bears!)

Novice Trade: Apple

Novice Trade: Apple

Everything You Need to Know About Closed-End Funds to Boost Your Portfolio

Everything You Need to Know About Closed-End Funds to Boost Your Portfolio