Bookie's concern
I believe the answer is:
odds
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">bookie's concern</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for odds that I've seen before include "(In betting) chances" , "Ratios set by bookies" , "at this is in dispute" , "Starting price" , "Measure of probability" .)