Home Depot ( NYS: HD ) is one of the large-cap stocks that hit a new 52-week high last week. That's not the case, however, for home improvement competitor Lowe's ( NYS: LOW ), which reported earnings this morning. The average observer might expect earnings from Lowe's to mirror Dow component Home Depot's better-than-expected report from last week, but that hasn't been the case lately. The company has underperformed consistently since the beginning of 2009, with same-store sales at Lowe's trailing Home Depot by an average of 1.8% per quarter. That continued today when Lowe's posted a same-store sales decline and lowered its full-year outlook. That underperformance and the resulting market share losses are reflected in the company's share price, which is up only 24% since the beginning of 2009, versus 141% for Home Depot.