** Bernstein initiates coverage of six European food retailers, noting that the companies, lacking dominant scale, must become "hot niche" drivers or transform to deliver strong returns
** "Competition is typically intense and ... most grocers are prisoners of scale," the brokerage says
** "Retail is a promise, and execution is everything," it adds, seeing physical stores as crucial to success
** Bernstein initiates UK-based Marks & Spencer MKS.L at "outperform", saying its food division occupies a high-quality niche while the clothing unit is set to improve margins
** It also starts Polish convenience store chain Zabka ZAB.WA at "outperform", citing its credible store opening plan
** It rates Britain's B&M BME.L, Poland's Dino DNP.WA and Sweden's Axfood AXFO.ST at "underperform", based on intensifying price competition and tightening profit margins
** It initiates Colruyt COLR.BR at "market-perform", seeing no significant improvement for the Belgian retailer, even though it forecasts stabilizing margins
(Reporting by Zakarya Meliani)
((zakarya.meliani@thomsonreuters.com))