** London-listed shares of refractory products supplier RHI Magnesita NV RHIM.L RHIM.VI slides 12.5% to 2,565p
** Stock set for biggest pct loss since March 2020, if trend holds
** Expects adjusted EBITDA for full year to be between 370 million euros and 390 million euros ($427.42 million - $450.53 million), compared to 407 million euros reported last year
** Including session's moves, stock down 20.3% YTD
($1 = 0.8657 euros)
(Reporting by Subiksha S in Bengaluru)
((Subiksha.S@thomsonreuters.com))