What happened

Kroger (NYSE:KR) investors outperformed the market by a wide margin last month as shares gained 25%, according to data provided by S&P Global Market Intelligence.

^SPX Chart

^SPX data by YCharts.

The surge only erased a portion of recent shareholder losses, though. In fact, the supermarket chain remains down by over 20% in 2017, compared to an 18% gain for the S&P 500.

So what

Kroger announced surprisingly strong earnings results late in the month, highlighted by its third consecutive quarter of improving sales growth trends. Comparable-store sales gains passed 1% to mark its best performance on that metric since mid-2016. Kroger posted healthy customer traffic, too, as the retailer added market share in a competitive selling environment.

A customer shops for cleaning supplies.

Image source: Getty Images.

Now what

Kroger affirmed its full-year profit outlook, meaning investors can count on lower earnings in 2017 -- mainly thanks to price cuts aimed at defending its market share. The good news is that these efforts appear to be working, since Kroger predicted that the current quarter will mark its fourth straight period of accelerating comps gains.

The retailer's long-term growth plan relies on expanding its home delivery and online ordering offerings to more of its locations in 2018. Kroger is also excited about the opportunity it sees in moving into the prepared food niche, which could double its addressable market over time. Accelerating comps numbers, however modest, are important steps toward that longer-term vision.

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