** Shares of Lynas Rare Earths LYC.AX fall as much as 5.8% to A$6.565

** Stock among top losers in the ASX 200 benchmark index .AXJO, which is down 0.2%

** Rare earths producer posts HY net profit after tax of A$5.9 million ($3.74 million), missing Visible Alpha consensus estimate of A$36.2 million

** Cites weak prices for metals due to subdued demand from China, higher operating costs

** Market conditions remain unpredictable, and Lynas' success will depend on its continued ability to balance growth ambitions with disciplined financial management - Jefferies

** Stock has risen 4.2% this year, as of 0101 GMT

($1 = 1.5763 Australian dollars)

(Reporting by Roshan Thomas in Bengaluru)

((Roshan.Thomas@thomsonreuters.com))