** Shares of James Hardie JHX.AX set for their weakest trading week since mid-March 2020
** Stock down 16.7% so far this week, set for third week of consecutive losses
** Fibre-cement maker announces $8.75 billion to buy U.S. artificial decking maker AZEK AZEK.N earlier in the week
** Morgan Stanley analysts note the deal to have "a heavy premium and elevated multiple", anticipating market to be skeptical of revenue synergy targets
** YTD, stock is down 22%
(Reporting by Sneha Kumar in Bengaluru)
((Sneha.Kumar@thomsonreuters.com))