Staples ( SPLS) posted earnings that handily beat expectations as revenue and margins continued to improve. The stock closed Tuesday at $18.39, up $2.16 or 13.31%. The office-supply retailer said third-quarter net income totaled $128 million, or 27 cents a share, up from $91.3 million, or 20 cents a share, a year earlier. Wall Street expected the company to earn 24 cents a share, according to Thomson Financial/First Call. Staples also said it expects to meet fourth-quarter estimates of 32 cents. The results, which Staples attributed to "stronger than expected top-line growth, solid margin growth and continued success in improving operating margins," bucked the downward earnings trend among other retailers posting this week. Sales were $3.1 billion, compared with $2.8 billion a year ago. Comparable store sales grew 3%, the company said, in part due to gains in its online operations. Retail-only comparable sales increased more than 1%.