Christmas trading statements from the retailers have been trickling in and Tuesday sees High Street bellwether Marks & Spencer (M&S) take its turn on the podium to update on trading in the final three months of 2010.Panmure Gordon is forecasting that M&S will achieve a year on year like for like (LFL) improvement of 1.0% on the General Merchandise side of things in the second half of the company's fiscal year (which runs to end-March) while Food sales are seen rising 1.7% on a LFL basis. "Within this, the strength of Q4 comps [comparative figures] last year mean that our forecasts would require perhaps +2.0 to +2.5% LFLs in General Merchandise and +2.0% LFLs in Food to be reported tomorrow," the broker notes. The broker sounds a little uncomfortable with this forecast, suggesting that the bad weather might have made it trickier for "the upper end of M&S's slightly older customer base" to make it to the company's stores during December."On the other hand, M&S has done well in terms of its multichannel model, which has proved to be an advantage thus far into the reporting season, so that this is one of the trading statements for which we think there is least visibility," the broker added. Financial services business Matrix Group notes that M&S's third quarter update this time round "will include the final week of Dec (unlike 2009), which is the important first week of the sale." The change benefits the reported Q3 number, although the company will also give the same-calendar basis number. Matrix is looking for a 4% boost in LFL sales in General Merchandise and a 2.5% jump on the Food side. "M&S should have traded relatively well in poor weather, given convenient locations, "comfort food" offer and inclusion of warm/basics clothing in the mix. Strong growth in Online sales should have continued: last seen +49%," Matrix adds. The full year gross margin guidance will be of interest to Matrix. Current guidance is flat, and given the challenges to pricing faced in 2011 there must be doubts whether even M&S can maintain margins, Tom Gadsby suggests.Bedding and home furnishings retailer Dunelm may not be as well known as Marks & Spencer but it is on a fast growth path and is Panmure Gordon's top pick for 2011 in the retail sector."Over the Christmas period, the shares have been marked down, we believe, on expected short term effects of wintry weather, which could imply a weak Christmas trading statement, due tomorrow, when we expect a flat to mildly negative LFL result," the broker said. In making an investment case for the stock Panmure Gordon notes that the retailer is less dependent on Christmas trade than other retailers in its investment universe, and the broker has a point; no one rips open a Christmas present hoping it will be a pillow case or a set of net curtains. "With reference to the snow, we are interested to note the emerging popularity of the website (which may be weather related), now in tenth place among Home and Garden websites in the UK per Experian Hitwise data, from very low visibility before," the broker adds. The British Retail Consortium (BRC) retail sales monitor will be released a breath after midnight and should provide further fuel to the debate about how much the winter weather affected retailers in December.INTERIM DIVIDEND PAYMENT DATEDods Group , TR Property Inv Trust, TR Property Inv Trust Sigma Shares, Whitbread, WincantonQUARTERLY PAYMENT DATEAfrica Opportunity Fund Ltd.INTERNATIONAL ECONOMIC ANNOUNCEMENTSMoney Supply (JPN)Current Account (JPN)Trade Balance (JPN)Bank of France Business Sentiment (FRA) (07:30)NFIB Small Business Optimism (US) (12:30)Wholesale Inventories (US) (15:00)ABC Consumer Confidence (US) (22:00)UK ECONOMIC ANNOUNCEMENTSBRC Retail Sales Monitor (00:01)RICS House Price Balance (00:01)GMSAsset Management Investment Co, Chrysalis, Davenham GroupFINALSIDOXEGMSForesight 4 VCT, Greenwich Loan Income Fund Ltd.AGMSBaronsmead VCT, Baronsmead VCT 2, Carr's Milling Industries, Debenhams, Topps TilesTRADING ANNOUNCEMENTSComputacenter, Dunelm, Marks & Spencer, Signet Jewelers Ltd.FINAL DIVIDEND PAYMENT DATERSM Tenon Group, Sportingbet, Waterman Group