Unsurprisingly, solar stocks are giving back some of their big 2013 gains (TAN -3.7%) in response to First Solar's (FSLR -16.1%) Q4 results and guidance. LDK -9.6%. SCTY -7.7%. SPWR -6.2%. YGE -6%. TSL -4.5%. JASO -4.4%. GTAT -2.9%. Piper and Baird have joined BofA in downgrading FSLR. On the earnings call, management said it's targeting a 2013 book-to-bill of at least 1 (it was 0.8 in 2012), but cautioned it expects 2H results to be weaker than 1H results due to upcoming project completions and a greater mix of module sales.