Answer:

share

AnswerCrossword Clue
SHARETwitter : retweet :: Facebook : ...
SHAREPiece of the pie
SHAREGo halfsies on
SHARESocial media button
SHAREStock unit
SHAREFacebook button
SHARENot hoard
SHAREPiece of the action
SHAREInvestment unit
SHAREMarket purchase
SHARECut
SHAREDon't hog
SHARENot hog
SHAREPercentage
SHAREOpposite of hog
SHAREDon't be a hog
SHAREPortion
SHAREWhat a certificate may represent
SHAREDividend earner
SHARERound lot unit
SHARELot
SHAREQuota
SHAREBrokerage unit
SHARELion's amount?