Stocks ticked lower during calm trading last week, which was shortened by the Christmas holiday. The minor decline still left investors staring at significant gains in 2017. For the full calendar year, the Dow Jones Industrial Average (^DJI -0.38%) rose by over 25%, while the S&P 500 (^GSPC -0.45%) logged a 20% jump.

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Several big-name earnings reports are on tap for the first trading week of 2018, including announcements from PriceSmart (PSMT 2.51%), Sonic (SONC), and Constellation Brands (STZ -0.15%). Let's look at a few key trends investors will be watching for in these results. 

PriceSmart's Colombian business

International warehouse club PriceSmart kicks off its fiscal 2018 by posting results after the market closes on Thursday. The retailer's last quarterly outing didn't give investors much good news to celebrate, and that stumble helps explain why the stock underperformed the market in 2017.

The quarter was marked by steady, but unspectacular, growth as comparable-store sales held to a 2% rate. U.S.-based peer Costco, in comparison, grew comps by 8% in its latest quarter. While a healing Colombian economy lifted PriceSmart's results, those gains were mostly offset by contractions in other markets, particularly Trinidad.

Outside a PriceSmart warehouse.

Image source: PriceSmart.

PriceSmart's latest operating figures should be a bit stronger. Comps for the month of November, which includes the start of the critical holiday shopping season, improved by nearly 3%, the company said in early December.

Investors will be looking for that growth uptick to come paired with membership gains and healthy renewal rates. PriceSmart's long-term outlook depends on its ability to expand beyond its small footprint of just 40 warehouses spread across Latin America and the Caribbean. But short-term results can often be rocked by instability in one or more of its major markets, so shareholders must be prepared for volatility as areas like Trinidad, Colombia, and Jamaica turn in varied levels of economic growth.

Sonic's customer traffic

Sonic posts its results on Thursday afternoon. The country's biggest drive-in restaurant chain is hoping to turn the page from a disappointing fiscal 2017, during which revenue declined 3.3%. "Sales were slower than we would have liked," CEO Cliff Hudson told investors in mid-October after the fast-food chain posted surprisingly soft fourth-quarter revenue, while blaming intense competitive activity with reducing its customer traffic. Industry leader McDonald's, on the other hand, grew comps by 6% in the same period.

Hudson and his team are targeting a return to positive comps in the new fiscal year. To get there, executives are making changes to their marketing approach to try to deepen the company's connection with its most loyal drive-in fans. Investors will be watching these results for signs that the advertising shift is working. In the meantime, look for Sonic's more heavily franchised business to generate stronger cash flow and profitability in 2018, even if sales growth remains weak.

Constellation Brands' beer sales

Constellation Brands shareholders trounced the market in 2017 as the alcoholic beverage giant announced sharply higher sales and profits. Its premium imported beer portfolio, anchored by the Corona and Modelo franchises, is enjoying particularly robust demand these days. Last quarter, that segment grew 13%, even as profit margin jumped to 41% of sales from 37%, due to higher selling prices.

Four friends drinking beer at a bar.

Image source: Getty Images.

Investors are expecting more market-leading sales growth and profitability when Constellation Brands posts its fiscal second-quarter numbers before the market opens on Friday. Given the sharp run-up in the stock lately, shares might decline in reaction to anything less than stellar operating results.

Regardless of that short-term volatility, though, the big-picture outlook looks bright for this company. Constellation Brands is nearly finished expanding its Mexican brewery capacity, and as capital spending slows back down, management is targeting at least $1 billion of annual free cash flow, much of which it can return directly to shareholders, starting in 2018.