According to Supermarket News a study conducted by University of North Carolina showed that entry of a Lidl store in April 2019 on Long Island resulted in reduced prices posted by major competitors.  Dr. Katrijn Gielens of the Kenan-Flagler business school conducted a survey on 27 stores following the opening of the first of four Lidl stores in December 2018 in Beth Page, NY.  The Lidl opening followed conversion of Best Market stores acquired in Nassau and Suffolk counties. 

This study showed that prices posted by Aldi declined by 14.9 percent, Wal-Mart by 8.5 percent and Costco by 8.3 percent. Reduction in price of four percent to five percent were recorded at Stop and Shop, BJ’s, Trader Joe’s and Target.

Dr. Gielens noted “this price pressure effectively resulted in retailers cutting prices up to 15 percent on specific items” She added “this price cutting effect is substantially greater than what is typically observed in previous academic studies on Wal-Marts entering new markets where price decreases typically vary by between one percent and five percent at most.  The entry of Lidl reversed price increases introduced by competitors after Best Market stores were closed.  Competitors including King Kullen, Stop and Shop raised prices by 12 percent and 9 percent with other stores raising prices from 2 to 8 percent.  Effectively the advent of Lidl trading in the converted Best Market stores reversed the price hikes.

By March 2020 Lidl was approximately 10 percent lower in price in 26 categories compared to competitors although some items were priced higher than the regional average.

The study conducted by Dr. Gielens reviewed the effect of Lidl on U.S. markets beyond Long Island and confirmed studies conducted in 2018 that demonstrated that Lidle exerted a significant level of pressure on other grocers.