** Shares of online review platform Trustpilot TRST.L down 9.3% at 213.8 pence
** Stock is second-top loser on FTSE mid-caps .FTMC index, which is flat
** Advent Global Opportunities sells 21.6 million Trustpilot shares at 214 pence per share for 46 million pounds ($61.75 million), Deutsche Bank says, implying a 9.2% discount to Monday's close
** Separately, co appoints The Economist Group CFO Marcus Roy as new finance chief
** YTD, TRST up about 30% vs .FTMC's nearly 6% fall
($1 = 0.7449 pounds)
(Reporting by Nithyashree R B in Bengaluru)
((NithyashreeRB@thomsonreuters.com))