Alphabet rises on Q1 revenue beat, share buyback plan

** Shares of Google-parent Alphabet GOOGL.O up 3.7% at $167.1 in extended trading

** GOOGL unveils a $70 billion share buyback

** Co reports Q1 total revenue of $90.23 billion compared to analysts' average estimate of $89.12 billion, according to data compiled by LSEG

** Q1 EPS of $2.81 beats estimates of $2.01

** GOOGL posts cloud revenue of $12.26 billion vs est. of $12.27 billion

** Up to last close, stock had fallen 15.7% YTD