Reduced by 50% (6)
I believe the answer is:
halved
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">reduced by 50%</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for halved that I've seen before include "Reduced by 50 per cent" , "Cut in two equal parts" , "Divided by two" , "Bisected" .)