Wallace Weitz is optimistic about the prospects of XO Group Inc (NYSE : XOXO ) and has increased his fund's holding of the stock. In a recently amended filing with the Securities and Exchange Commission, Wallace R. Weitz & Co. has disclosed an increase from 2.65 million to 2.80 million shares, which account for 10.44% of the company's common shares. This is the second time this year that Weitz increases his position in XO Group, after adding approximately 30,000 shares in January.