Nomura has retained its 'buy' rating for High Street group Marks & Spencer (M&S), saying that while the hot summer weather and promotions are likely to have been unhelpful in the second quarter, there is little to suggest it is an underlying problem.Given tough comparatives with last September (which saw 9% growth), Nomura is looking for a flat September this year, leading to a 0.4% decline in like-for-like (LFL) sales in the second quarter (three months to September 29th).The broker said that following the first-quarter update in July, M&S was already behind its above-consensus full-year forecasts. "Since then, we expect the early summer sale in June, prior to the heat wave, will have been unhelpful in driving 2Q full-price sales. The industry in general has struggled against tough promotional comparatives and warm temperatures," said analyst Fraser Ramzan.He said that he has reduced his full-year profit before tax forecast by £25m, after cutting LFL growth and margin estimates for General Merchandise (GM), offset slightly by an increase to the expected gross margin growth for food retail.Nevertheless, the new profit before tax estimate of £677m still remains above consensus forecasts before recent downgrades. Ramzan said that the 12% decline in profits in the first half should be countered with a 18% improvement in the second half."We are bullish on UK retail, with M&S LFLs highly correlated to consumer confidence, which has been rising sharply in recent months. We also believe M&S is substantially under-earning in margin terms with GM gross margins 51% versus 57-60% for peers. "The current strategy to improve product availability and reduce markdown issues in our opinion will significantly narrow this gap, and we believe the division has a credible management team in place to execute on the strategy."Nomura maintained its 540p target price. The stock was up 0.22% at 464.8p on Wednesday morning.BC