Corporate marriage (6)
I believe the answer is:
merger
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">corporate marriage</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 merger that I've seen before include "Unification" , "The combining of two companies into one" , "Joining of businesses" , "Joining (of companies)" , "Act of combining" .)