What: Discount retailer Big Lots (NYSE:BIG) jumped 13% in May, according to data provided by S&P Global Market Intelligence.

BIG Chart

BIG data by YCharts.

The bounce contributed to a nice run for shareholders, who are now up 30% through the first five months of 2016. Big Lots is also beating the market over the past full year, with a 17% return compared to just a 2% uptick for the S&P 500.

So what: Shares rose last month in response to a quarterly earnings announcement that showed the retailer is expanding at its strongest growth pace since 2011. Revenue improved by 3% at existing locations, or more than three times the rate it had seen over the holiday season quarter.

That success put Big Lots in a small class of retailers, mostly on the discount side of the market, that are posting better growth these days as established full-price sellers like Target (NYSE:TGT) struggle. For its part, Target barely managed to break 1% comps, even though it benefited from the inclusion of a robust e-commerce business.

Big Lots also had Target beat on profitability, with gross margin holding steady at 39% of sales compared to the retailing titan's 31%. The healthy margin figure implies that Big Lots didn't have to slash prices to keep its customer traffic figures churning higher. In a press release, CEO David Campisi credited "improved merchandise presentations and more consistent in-store execution" for the market-beating gains.

Now what: Campisi and his team are hoping to keep the Q1 momentum going into the summer months through national merchandising initiatives that focus on its best product categories (like furniture) and a new private-label credit card to drive repeat business.

The company didn't boost its sales forecast and still expects comps growth of around 2% in the current quarter and in the "low single digits" for the full year. Meanwhile, expenses are slated to rise as Big Lots pours resources into finally establishing its e-commerce presence.

As rival retailers already get a significant chunk of their growth from online business, it's likely Big Lots will eventually see a similar boost. However, a cautious approach to the website roll-out will ensure that major benefits aren't going to begin accruing until 2017.

Demitrios Kalogeropoulos has no position in any stocks mentioned. The Motley Fool recommends Big Lots. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.