Ross Stores Inc, retailer of low-priced apparel, reported a 21-percent increase in quarterly profit on Thursday as margins improved.

The company also raised its forecast for full-year earnings, though this, and its forecast for the second quarter, were still shy of analysts' estimates.

Ross's profit rose to $208.60 million, or 93 cents a share, in the first quarter through April 28, compared with $173 million, or 74 cents a share, a year earlier. Analysts on average forecast 93 cents a share, according to Thomson Reuters I/B/E/S.

Earlier this month, the company said first-quarter sales grew 14 percent to $2.36 billion, with sales at stores open at least a year up 9 percent.

For the second quarter, Ross expects same-store sales to rise 3 percent to 4 percent, with earnings per share of 72 cents to 75 cents. For the full year, it expects earnings per share of $3.26 to $3.37, up from its previous forecast of $3.12 to $3.27.

Analysts, on average, forecast 76 cents a share for the quarter and $3.38 a share for the year. (Reporting by Brad Dorfman. Editing by Bernadette Baum)