You're comparing to the wrong competitors. Home health stocks are the ones that have gone down drastically in the last 5 days. CHE and LNCR are not home health stocks. (CHE is a competitor in hospice, but AMED's primary business is home health.) Here is a 5 day comparison with home health companies: http://finance.yahoo.com/q/bc?s=AMED&t=5d&l=on&z=m&q=l&c=GTIV,LHCG,AFAM
By the way, when compared to these companies AMED has held up well not just looking at the last 5 days, but a month, 3 months, 6 months.