CHICAGO—A new report by Numerator quantifies the showrooming effect, which is when consumers browse a brick-and-mortar store and then buy online, according to a news release. The analysis covers cross-shopping behavior among the largest U.S. retailers, including Amazon, Walmart, Target and Costco—specifically, consumers who supplement in-store shopping trips with an Amazon purchase within one day.

According to the report, roughly three-quarters of major retailer shoppers also shop at Amazon. Over half (53%) of Walmart shoppers made an Amazon purchase within a day of shopping in-store at Walmart, compared to 38% of both Target and Costco shoppers.

Numerators says Target has the largest opportunity to capture lost day-of sales to Amazon. By preventing leaked same-day trips to Amazon, Target has the potential to capture 10.3% in incremental sales, followed by Walmart (+7.2%) and Costco (+4.7%). General merchandise items make up the majority of leaked sales to Amazon. The top four leaked categories (home and garden, electronics, health and beauty, apparel) accounted for over half of all leaked dollars at each retailer.

Home and garden products at Walmart had the highest percentage of leaked sales (18.5%) among all categories and retailers. Electronics leakage was highest at Costco (15.9% of leaked sales), followed by Walmart (14.9%) and Target (14.2%). Target was the only retailer to have grocery appear in the top five leaked categories (5.2% of leaked sales).

Those surveyed by Numerator said that product availability and ease of delivery were top reasons cited for buying on Amazon after shopping in-store. Thirty percent of Walmart-to-Amazon shoppers said they made the Amazon purchase due to lack of product availability in-store, six points higher than reported by Target shoppers (24%). Nearly one-third of both Target and Walmart shoppers claimed “ease of delivery” as their reason for buying on Amazon despite being in the brick-and-mortar store that same day.