Image source: BJ's Restaurants.

What: Shares of BJ's Restaurants, Inc. (NASDAQ:BJRI) slipped 11.4% last month according to data from S&P Global Market Intelligence as the company turned in a subpar second-quarter earnings report. As you can see from the chart below, the entirety of the stock's fall came on July 27 after the report came out.

BJRI Chart

BJRI data by YCharts.

So what: Reflecting a trend in the restaurant industry, BJ's said comparable sales declined 0.2%, though revenue increased 7.9% to $250.3 million as the company continued to open new restaurants. That figure was below the consensus at $253 million. Earnings per share, meanwhile, increased 19.5% $0.56, missing estimates by a penny.

CEO Greg Trojan was positive on the company's overall trajectory, but did acknowledge that comparable sales were softer than expected. 

Now what: Management did not provide guidance for the current quarter, but said that comparable sales were down 2% thus far in July, blaming a weakening consumer environment. Over the long term, the company stressed that it has room to more than double its restaurant count from 177 today to 425. It's also targeting lower-cost, smaller-format restaurants that should provide a faster return on investment.

Still, declining comparable sales are always concerning for restaurants, and with the trend aiming downward, the stock could follow.