By Aditya Kalra

NEW DELHI (Reuters) - Indian antitrust investigations have found that Amazon and Walmart's Flipkart violated local competition laws by giving preference to some sellers, prioritising certain listings, and steeply discounting products, hurting other companies.

Here are the key findings of the Competition Commission of India (CCI), which are detailed in two reports that are not public but have been reviewed by Reuters.

Amazon, Flipkart and the CCI have not responded to requests for comment about the reports.

* PREFERRED SELLERS: Amazon had six preferred sellers, while Flipkart had 33, who got preferential treatment on their platforms in breach of antitrust laws. The sellers received marketing, warehousing and other services at a "miniscule cost".

The CCI also said Amazon and Flipkart used their foreign investments to provide such subsidised rates.

There was an ecosystem at both Amazon and Flipkart "wherein no seller other than its preferred seller can survive", the CCI said.

*PREFERENTIAL LISTINGS: The CCI said that the majority of products appearing at the top of Amazon and Flipkart listings were from alleged preferred sellers. This created a barrier for other sellers, the CCI said.

* EXCLUSIVE PRODUCT LAUNCHES: Both Amazon and Flipkart had partnerships with smartphone and technology companies to launch their devices exclusively, a move that hurt smaller retailers.

"Exclusive launches had not only severely affected the ordinary sellers on the platform but also the brick-and-mortar retailers who were provided mobile phones at a much later date," the CCI reports said.

* DEEP DISCOUNTING: Both Amazon and Flipkart enabled their affiliated and preferred sellers to provide deep discounts, which involved selling much below cost for the purpose of driving out competition, the CCI reports said.

(Reporting by Aditya Kalra; Editing by Mark Potter)