BUZZ-Sophos: Q1 warning spurs cyber-security co's worst day ever
** Sophos down c19 pct, biggest ever one-day drop (IPO: mid 2015)
** Co expects to report lower than anticipated billings growth in Q1 - at c2 pct at constant currency (vs Morgan Stanley (Xetra: 885836 - news) estimate of 12 pct)
** Co says subdued Q1 growth mainly driven by Enduser security business, which faced a particularly challenging comparable
** MS highlights co's expectation of continued weak growth in billings in Q2, before moving back to mid teens billings growth ex FX in H2
** Stock -12 pct YTD