Shares of Sears Holdings Corp. plunged 17.9% in midday trade Friday, putting it on track for the biggest one-day drop in three years, in the wake of the struggling department store chain's disappointing fiscal first-quarter report and announcement of more store closures. On Thursday, the stock tumbled 12.5%. The stock has now shed 33.8% this week, which would be its biggest-ever weekly percentage decline, despite it being just a four-day week, since the stock began trading in its current form in April 2003. Susquehanna analyst Bill Dreher reiterated his negative rating and stock price target of $2.00, which is 13% below current level, saying the results show that "performance erosion accelerates" as the company's talking points ring more hollow. "The environment for Sears is only going to get more competitive as other larger, more profitable retailers get a boost from lower tax rates and reinvest in their business, which Sears would not be able to do," Dreher wrote in a note to clients. The stock has plummeted 69.4% over the past 12 months, while the SPDR S&P Retail ETF has climbed 11.8% and the S&P 500 has rallied 12.5%.