Now playing
03:46
Rush shipping is often free. But the environment could be paying for it
WASHINGTON, DC - JUNE 22: Facebook
WASHINGTON, DC - JUNE 22: Facebook's Chief Operating Officer Sheryl Sandberg speaks with AEI president Arthur C. Brooks during a public conversation on Facebook's work on 'breakthrough innovations that seek to open up the world' at The American Enterprise Institute for Public Policy Research on June 22, 2016 in Washington, DC. (Photo by Allison Shelley/Getty Images)
PHOTO: Allison Shelley/Getty Images North America/Getty Images
Now playing
01:23
Hear Sandberg downplay Facebook's role in the Capitol riots
screengrab US social media
screengrab US social media
PHOTO: Getty Images
Now playing
04:35
Tech companies ban Trump, but not other problematic leaders
PHOTO: Samsung
Now playing
01:53
See Samsung's new Galaxy S21 lineup
PHOTO: CNN
Now playing
02:47
Extremists and conspiracy theorists search for new platforms online
This illustration picture shows the social media website from Parler displayed on a computer screen in Arlington, Virginia on July 2, 2020. - Amid rising turmoil in social media, recently formed social network Parler is gaining with prominent political conservatives who claim their voices are being silenced by Silicon Valley giants. Parler, founded in Nevada in 2018, bills itself as an alternative to "ideological suppression" at other social networks. (Photo by Olivier Douliery/AFP/Getty Images)
This illustration picture shows the social media website from Parler displayed on a computer screen in Arlington, Virginia on July 2, 2020. - Amid rising turmoil in social media, recently formed social network Parler is gaining with prominent political conservatives who claim their voices are being silenced by Silicon Valley giants. Parler, founded in Nevada in 2018, bills itself as an alternative to "ideological suppression" at other social networks. (Photo by Olivier Douliery/AFP/Getty Images)
PHOTO: Olivier Douliery/AFP/Getty Images
Now playing
03:49
Parler sues Amazon in response to being deplatformed
PHOTO: Twitter
Now playing
02:39
Twitter permanently suspends Donald Trump from platform
Panasonic
Panasonic's Augmented Reality Heads-up Display
PHOTO: Panasonic USA
Now playing
01:06
This tech gives drivers directions on the road in front of them
PHOTO: LG Display
Now playing
01:10
See LG's transparent TV
PHOTO: Twitter/@gregdoesthings
Now playing
02:06
Internet gets creative with empty iPhone boxes
NEW YORK, NY - JUNE 3: The Google logo adorns the outside of their NYC office Google Building 8510 at 85 10th Ave on June 3, 2019 in New York City. Shares of Google parent company Alphabet were down over six percent on Monday, following news reports that the U.S. Department of Justice is preparing to launch an anti-trust investigation aimed at Google. (Photo by Drew Angerer/Getty Images)
NEW YORK, NY - JUNE 3: The Google logo adorns the outside of their NYC office Google Building 8510 at 85 10th Ave on June 3, 2019 in New York City. Shares of Google parent company Alphabet were down over six percent on Monday, following news reports that the U.S. Department of Justice is preparing to launch an anti-trust investigation aimed at Google. (Photo by Drew Angerer/Getty Images)
PHOTO: Drew Angerer/Getty Images North America/Getty Images
Now playing
03:25
Google employee on unionizing: Google can't fire us all
Now playing
02:01
Watch 'deepfake' Queen deliver alternative Christmas speech
Now playing
01:42
Watch father leave daughter dozens of surprise Ring messages
PHOTO: Photo Illustration: Kena Betancur/Getty Images
Now playing
04:50
Zoom's founder says he 'let down' customers. Here's why
Now playing
00:48
See Walmart's self-driving delivery trucks in action
Now playing
01:25
This robotaxi from Amazon's Zoox has no reverse function
(CNN Business) —  

Amazon will no longer allow its third-party sellers to use FedEx’s ground delivery to ship Prime packages, marking a change that could affect small businesses and pricing for consumers.

The move was highlighted in an email, obtained by The Wall Street Journal, reportedly sent to Amazon’s merchant partners on Sunday.

The email noted performance declines as the reason for the decision to block FedEx (FDX) Ground, according to the Journal. The ban will reportedly take effect this week and last “until the delivery performance of these ship methods improves.”

As of September, Amazon (AMZN) no longer uses FedEx for its own deliveries but it had allowed third-party sellers to use it. Amazon (AMZN) did not release a statement but will still allow merchants to use FedEx’s more expensive Express service for Prime orders and Ground for non-Prime shipments, according to Amazon (AMZN).

FedEx said in a statement to CNN Business that the decision only affects a small number of shippers. But it said the move may impact these small sellers’ ability to manage their businesses by limiting their options “on some of the highest shipping days in history.”

The move comes as the holiday season — a time when more packages are shipped than at any other point of the year — hits its peak. It’s also a time when carriers face inclement weather, which can affect shipping times, and this year there are fewer days between Thanksgiving and Christmas, meaning more volume over a shorter time span.

Amazon’s focus on speeding up delivery times and its aggressive work to beef up its own shipping network threaten established shipping companies such as FedEx and UPS (UPS).

FedEx and Amazon have launched rival initiatives in recent years. For example, when Amazon debuted single-day delivery, FedEx announced Sunday delivery. And when Amazon started testing a delivery robot, FedEx launched the SameDay bot.

The companies have had a tumultuous relationship of late. In June, FedEx chose not to renew a contract with Amazon to transport packages on FedEx planes. In August, FedEx announced it would let its ground ship contract with Amazon expire at the end of the month.

FedEx has denied that parting ways with Amazon is bad for its business, citing its ability to focus on other e-commerce partnerships. FedEx has deals with Walmart (WMT) and Walgreens (WBA) for next-day shipping and a partnership with Target (TGT) that allows it to use stores as local shipping hubs.