** Shares of biotechnology giant CSL CSL.AX plunge 17.6% to A$151.350 in early trade, their lowest since mid-February 2018
** Marks biggest intraday fall on record
** Stock also top loser on the benchmark ASX200 .AXJO, which is up 0.4%
** CSL on Tuesday also tapped insider Gordon Naylor as interim CEO following Paul McKenzie's retirement, seeking to calm investor nerves over falling U.S. vaccination uptake and softer profit momentum
** Posts underlying HY net profit after tax attributable of $1.92 billion on a constant‑currency basis, down from $2.11 billion a year earlier
** Stock down 6.4% YTD as of last close
(Reporting by Kumar Tanishk in Bengaluru)
((Tanishk.Kumar@thomsonreuters.com; X: @thatstanishk http://www.x.com/thatstanishk;))