The Investor Day presentation by High Street giant Marks & Spencer (M&S) on 13 October backfired, with investment analysts underwhelmed by the presentations from senior executives, some of whom are jostling for position in the contest to succeed Sir Stuart Rose as chief executive officer next year.The share price reacted negatively on a day when a viable external candidate, former M&S man Charles Wilson, the chief executive of cash and carry outfit Booker, ruled himself out of the running.Wednesday's interim results represent an opportunity for M&S to regain the initiative, and justify Rose's assertion at the Investor Day that the business is in 'pretty good shape'.The omens are not especially good, however; last month, figures from market research group TNS FashionTrak, indicated that M&S has fallen into third place among Britain's fashion chains, slipping behind George at Asda, which has a 10.1% market share, and Primark, a pip ahead of M&S's 9.8% share with 9.9% of the market.M&S downplayed the significance of the event, with a spokeswoman noting that 'value retailers tend to increase market share over the summer, whereas Marks & Spencer's market share improves over the winter.'With the Investor Day presentation only three weeks in the past, there should not be much new information to be imparted, though management may take the opportunity to address issues raised in the wake of the Investor Day, such as the progress on the streamlining of the company's supply chain and the modernising of its creaking IT system. The company may also announce the results of its triennial pension fund review.Charles Stanley expects Marks & Sparks to announce sales of £4.34bn, up from £4.22bn at the half-way stage last year, while profit before tax is tipped to ease to £290m from £298m.Fashion chain Next issues a trading statement covering trading in the second half of the year. The company will be going up against weak comparative figures so may be able to improve on a 2.5% year on year fall in like for like (LFL) sales at the half year stage. Cut price food and booze pubs group JD Wetherspoon will give a trading update at its annual general meeting, covering the first quarter of its financial year. In the first six weeks of the quarter, LFL sales rose 1.2%, and any increase on that rate will leave the company well placed to absorb the shock of the VAT increase, due to come into effect at 6:00am on New Year's Day.Transport group Firstgroup follows hot on the heels of sector peer Stagecoach with an interim results announcement. Broker Nomura Securities thinks the company is still facing a difficult trading environment, with the US Greyhound bus operation likely to suffer declining revenues. On a bright note, the broker believes first half earnings per share will represent the low point in the earnings cycle for Firstgroup. On the economic front, the service sector purchasing managers' index for October is expected to stick close to the 55.5 level seen in September, which was a two-year high.INTERIMSAlterian, FirstGroup, Marks & Spencer Group, UmecoINTERIM DIVIDEND PAYMENT DATECello Group, M. P. Evans Group, StatPro GroupINTERIM EX-DIVIDEND DATEBraemar Shipping Services, Collins Stewart, Edge Performance VCT, Havelock Europa, Hilton Food, Intertek Group, Northern 2 VCT, Provident Financial, SThreeQUARTERLY EX-DIVIDEND DATEEquity Partnership Income Shares, GlaxoSmithKline, JPMorgan Claverhouse Inv Trust, Royal Dutch Shell 'A', Royal Dutch Shell 'B'FINALSEdinburgh Dragon TrustINTERNATIONAL ECONOMIC ANNOUNCEMENTSFOMC Interest Rate (US) (19:15)ISM Non-Manufacturing (US) (15:00)PMI Services (EU) (09:00) PMI Services (GER) (08:55)Retail Sales (EU) PMI Services (FRA) (08:55) Bank of Japan MPC Meeting Minutes (JPN)EGMSBioenergy AfricaAGMSBioenergy Africa, Green CO2, Indigo Vision, JD Wetherspoon, RedrowUK ECONOMIC ANNOUNCEMENTSBRC Shop Price Index (10:30)PMI Services (09:30)Nationwide Consumer Confidence (00:01)FINAL EX-DIVIDEND DATEAbcam, Animalcare Group, Ashmore Group, Baqus, BlueBay Asset Management, Craneware, Go-Ahead Group, Henderson Far East Income Ltd., Indigo Vision, Interior Services, ISIS Property Trust, James Halstead, JPMorgan Overseas Inv Trus, Matchtech, Murgitroyd Group, Plexus, Quadnetics Group, St Ives, United CarpetsQUARTERLY RESULTSEndeavour International Corp, JD WetherspoonTRADING STATEMENTSAegis Group, Aviva, Cobham, Goldenport, Liberty International, Logica, MWB Group Holdings, Next, Pace, Pacific Horizon Inv Trust, Rightmove, WSP