Investors cheered Friday upon hearing the news that struggling Christopher & Banks’ sales rebounded this fall after a disappointing summer.

Preliminary results for the Plymouth-based women’s clothing retailer’s third quarter showed that comparable sales rose 4.5 percent, a much better showing than the same period a year ago when they dropped 6.7 percent amid merchandising misfires.

The company’s shares rose about 21.5 percent, or 26 cents, on Friday to close at $1.47.

Net sales in the quarter ended Oct. 29 rose 3 percent to $106.2 million at its 506 stores, up from $103.6 million while operating 533 stores in the same quarter a year ago.

“Overall, we are very pleased with our performance during the third quarter as our customers responded favorably to our merchandise assortment and our marketing efforts,” LuAnn Via, the retailer’s chief executive, said in a statement. “Our initiatives are beginning to take hold as we were able to drive positive comparable sales in all three months while maintaining gross margin, despite a continuation of negative mall traffic trends, a highly promotional environment and unseasonably warm weather.”

The company will report its official third quarter results on Dec. 1.

In August, the retailer reported a drop in sales in the second quarter, blaming the lower-than-expected performance partly on the transition to using a new e-commerce platform in May that included some technical difficulties.

Christopher & Banks has struggled to gain consistent momentum in a multiyear turnaround effort under Via. Earlier this year, as it faced heated scrutiny from an activist shareholder, the company overhauled its board. Six directors exited and four new members added to bring more retail expertise to the board.