Walmart down after quarterly profit miss

** Shares of retail bellwether Walmart WMT.N see-saw in volatile premarket trading, last down 2.5% at $99.96

** Co misses estimates for quarterly adjusted EPS for the first time in 13 quarters

** Q2 adjusted EPS of 68 cents missed expectations of 74 cents - data compiled by LSEG

** However, co raises annual forecasts after beating Q2 revenue expectations

** Now expects annual net sales to rise between 3.75% and 4.75%, up from previous 3% to 4% increase forecast

** Also sees annual adjusted EPS between $2.52 and $2.62, compared to its prior $2.50 to $2.60 forecast

** Up to last close, stock has risen 13.5% YTD