Shares of Caterpillar ( CAT) are down Thursday after the company significantly missed analysts' second-quarter earnings estimate despite a 40% increase in profit.The Peoria, Ill.-based construction equipment giant said earnings rose to $552 million, or $1.55 a share, from $399 million, or $1.15 a share, in the same period last year. Sales were up 27% to $7.56 billion from $5.93 billion in the prior year. The company said sales were driven by higher volumes in their machinery and engine divisions, increased price realization and an estimated $116 million favorable impact of currency on sales due to the strengthening euro. According to Thomson First Call, analysts had forecast earnings of $1.74 a share on revenue of $7.19 billion. Caterpillar said increased core operating costs reflected higher material costs due to surcharges and inefficiencies due to material availability, support costs to meet volumes, planned spending on product development programs and higher incentive compensation due to the company's increased outlook. The company boosted its full-year outlook, saying it now expects revenue to rise about 25% and earnings per share to increase 80% to 85%. Based on year-ago results, that would suggest earnings of $5.16 to $5.32 a share and revenue of $28.45 billion. The full-year consensus estimates are earnings of $5.56 a share on revenue of $26.51 billion. Shares of Caterpillar are recently down $4.75 or 6.17% to $72.20.