Sam Duncan has been in the CEO suite at Supervalu Inc. for 14 months now, and his mission to turn around the company is gaining momentum.

Eden Prairie-based Supervalu on Wednesday posted a strong fourth quarter, surpassing Wall Street's earnings and revenue expectations, and for the first time since 2008 showing an increase — albeit small — in same-store sales at its conventional grocery chains.

The supermarket company's stock jumped 11.5 percent, or 78 cents, closing at $7.54.

Duncan, a veteran retail executive, took the helm shortly after an embattled Supervalu sold its largest grocery chains last year, essentially halving the size of the company. Supervalu's fourth-quarter results marked its strongest quarter yet under Duncan.

"We think Supervalu has performed extremely well in its transition year under Sam Duncan and the leadership team," Ajay Jain, a stock analyst at Cantor Fitzgerald, wrote in a research note Wednesday.

Karen Short, an analyst at Deutsche Bank, wrote that Supervalu's management team "has done a great job of stabilizing and re-basing the business, taking out costs and improving the [balance sheet]. However, the road to sustained growth will be uneven," she added.

Supervalu posted net earnings from continuing operations of $40 million, or 15 cents per share, for the three months ended Feb. 22. When adjusted for one-time items including employee severance and debt financing costs, Supervalu reported earnings of 18 cents per share. It lost money in the same period a year ago.

Analysts polled by Thomson Reuters were on average expecting 15 cents per share for adjusted earnings.

Supervalu, which owns Twin Cities grocer Cub Foods, had sales of $3.95 billion, up 1.4 percent over the same time a year ago and almost 2 percent higher than analysts' expectations.

"I am pleased with the direction of our business segments and look forward to the new fiscal year where we can focus our attention on driving sales growth across the organization," Duncan said in a statement.

Duncan told analysts in a conference call that the company plans to continue lowering prices — to win back customers — and increase capital spending in its new fiscal year. Supervalu anticipates capital expenses of $230 million to $240 million, up from about $110 million in fiscal 2014.

During Supervalu's fourth quarter, all three of its divisions for the most part did better than expected.

At Supervalu's national discount grocery chain, Save-A-Lot, same-store sales were up 2.1 percent over a year ago, and rose sequentially over the third quarter.

Supervalu's conventional supermarket division saw same-store sales grow 0.2 percent, a baby step, but the first step forward since 2008. "I'm very encouraged by the progress we've made in retail," Duncan said during the conference call.

He credited the improvements partly to a newly decentralized management structure in the supermarket division. "Key to our performance is the improved store-level execution," Duncan said.

In addition to Cub, Supervalu owns supermarket chains in Missouri, Maryland, Virginia and North Dakota.

Supervalu's food distribution business, one of the nation's largest, saw sales fall 0.6 percent over a year ago to $1.82 billion. However, the decline was less than expected by stock analysts.

Total sales for conventional chains like Cub were $1.09 billion, while Save-A-Lot had sales of $999 million.

Mike Hughlett • 612-673-7003