This week's biggest % winners & losers (April 27 - May 1, 2015)

The following are this week's top 20 percentage gainers and top 20 percentage losers, categorized by sectors (over $300 mln market cap and 100K average daily volume).

This week's top 20 % gainers

• Materials:RYAM (19.12 +24.8%),TAHO (14.02 +18.01%)
• Industrials:CVEO (4.5 +31.2%),MRC (16.74 +21.66%),TWI (11.37 +21.09%),AAWW (51.95 +20.65%),GTI (4.83 +16.67%)
• Consumer Discretionary:NTRI(23.25 +16.25%)
• Information Technology:CKSW(12.43 +32.8%),GLUU (6.9 +26.61%),CYOU (34.51 +17.7%)
• Financials:OCN (10.26 +32.56%),NBG (1.45 +17.89%),ASPS (26.94 +15.92%)
• Energy:CRR (43.99 +39.21%),CLNE (10.27 +27.26%),PES (7.55 +22.76%),SDLP (15.66 +20.18%),CJES (17.4 +18.13%),SDRL (13.22 +16.07%)

This week's top 20 % losers

• Healthcare:CLDN (2.62 -80.85%),IG (5.22 -41.61%),ATRA (40.45 -32.46%),AERI (9.37 -27.2%),ADXS (17.07 -26.86%),CALA (9.82 -26.77%),ARAY(6.82 -25.23%),RGLS (13.47 -22.98%),HRTX (11.01 -22.36%),AKRX (43 -22.16%),TKMR (14.67 -21.76%),JUNO (44.82 -20.9%)
• Industrials:AMOT (30.68 -25.24%)
• Consumer Discretionary:MDCA (20.32 -28.45%),CTCM (3.35 -20.99%)
• Information Technology:CTCT (27.51 -29.64%),SSYS (36.71 -28.41%),TWTR(37.84 -25.54%),YELP (39.76 -21.44%),LNKD (205.21 -21.36%)