Amazon records strongest cloud growth in over four years, shares surge

** Shares of Amazon AMZN.O jump 11.4% to $262.32 premarket

** Co reports strongest cloud growth in more than four years and raises annual capital spending forecast

** Revenue at its cloud unit, AWS, jumps 37% to $42.2 billion, beating analysts' estimates of a 31.21% increase

** Raises annual capex forecast by 10% to $220 billion

** Stock recently at 25x expected earnings, well below its 5-yr avg forward PE of 45x, suggesting shares may be undervalued, per LSEG-compiled data

** YTD, shares up ~2%, underperforming the Nasdaq .IXIC which has risen ~8.1% in the same period