Shake Shack's (SHAK - Get Report) sales pressure will continue as new stores fail to garner the same level of excitement as generated by older ones, Goldman Sachs analyst Karen Holthouse said. 

"We have previously highlighted: Declining novelty and therefore excitement around unit opens as a risk to new store productivity, and cannibalization as a growing risk to traffic trends at SHAK, as the company continues to add density in markets outside of NY. In this report, we look at the Washington DC market (where SHAK just added its fourth unit on March 16, 2017) as a case study that largely confirmed both of these concerns," she wrote. 

She notes that new store openings garner lower levels of customer interest, as measured by both Twitter (TWTR - Get Report) and Yelp (YELP - Get Report) reviews. Interest that exists is driven largely by tourism as opposed to local traffic.

"Following our analysis, we update our model for the 10-K and lower expected new unit volumes; our 2017-19 EPS estimates are now lower by 4-9%," Holthouse said.