Shares of Signet Jewelers (SIG 0.09%) were moving higher this week after the world's largest retailer of diamond jewelry posted better-than-expected results in its fourth-quarter earnings report, and guided to positive comparable-sales growth in the first quarter.

As of Thursday at 11:15 a.m. ET, the stock was up 20.3% for the week on the news.

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Signet shines

Signet's post-earnings jump came as the company had lowered guidance earlier in the quarter after disappointing results for the holiday season.

However, the company adjusted its assortment and saw better performance to finish out the quarter, and that continued into the new year.

Overall revenue in the quarter was down 5.8% to $2.35 billion, but that was better than the company's guidance and the consensus at $2.33 billion. Same-store sales fell 1.1% in the quarter. On the bottom line, adjusted earnings per share slipped from $6.73 to $6.62, which beat estimates at $6.25.

Beyond the beats on the top and bottom lines, investors also seemed pleased with the shift in the company's momentum, as management noted "improved trends in bridal" and reported a positive comp in January.

The company's first-quarter guidance called for same-store sales growth of flat to 2%, showing it's on track for its first quarter of positive comps growth in three years.

What's next for Signet?

Even after Signet's gains this week, the stock is still significantly lower than it was before it cut its fourth-quarter guidance back in January, showing some investors have lost faith in the company.

New CEO J.K. Symancyk also announced a new strategic plan called Grow Brand Love, which the company hopes will improve brand loyalty and help return the business to steady growth. Additionally, Signet said it would raise its quarterly dividend to $0.32 a share, showing confidence in the business.

Overall, the jewelry stock looks cheap at a price-to-earnings ratio of less than 7, but Signet will have to prove it can deliver steady growth before the stock can return to its earlier heights.