Landstar System said late Wednesday that its board of directors has declared a quarterly dividend of 5 cents per share, which is payable on Aug. 27 to shareholders of record at the close of business on Aug. 9. Previously, the freight shipper paid a quarterly dividend of 4.5 cents per share. The dividend increase announcement came as Landstar posted second-quarter earnings of 49 cents a share on revenue of $641.7 million, which came in ahead of the Thomson Reuters average estimate for a profit of 48 cents a share on sales of $600 million. Shares of Landstar was trading lower in Thursday's premarket session, falling 1.2% to $40.99, after the company offered guidance for the third quarter. Landstar says it expects third-quarter earnings to fall in a range of 47 cents to 52 cents a share, which is in line with the company's second-quarter results as well as analysts' estimates. Landstar said it expects revenue to grow by 25% to 33% in the third quarter. Elsewhere, National Retail Properties ( NNN) said it has increased its quarterly dividend payment to 38 cents per share from 37.5 cents, an increase of 1.3%. The new dividend is payable on Aug. 16 to common shareholders of record on July 30, the real estate investment trust said. Shares of National Retail Properties closed flat Wednesday at $22.82. -- Written by Robert Holmes in Boston. Follow Robert Holmes on Twitter and become a fan of TheStreet.com on Facebook.