London's benchmark index opened tentatively on Thursday morning ahead of another big day for corporate earnings in the US.It looks to be a quiet morning for Europe with little data due out, so the focus is likely to be on debt auctions in Spain, as the Treasury attempts to sell 2015, 2018 and 2041 bonds."These auctions should go ok, mostly because Spanish yields have been relatively stable of late and other auctions in the past few weeks have shown good demand, especially as no major changes or events have taken place as Spain and the European financial crisis is concerned," said Markus Huber, the head of German HNW trading at ETX Capital.In contrast, the economic data schedule Stateside looks quite busy, with jobless claims, building permits, housing starts and the Philly Fed index due out later on. Meanwhile, Wall Street heavyweights Bank of America, Citigroup and Intel are scheduled to release their fourth-quarter earnings today.Huber said: "Despite US earnings season having gotten off to a very respectable start so far, the overall stock market is being held back from posting further major advances to the upside on increasing worries about the debt ceiling and concerns that global growth might not be picking up as much in 2013 as previously hoped with several major institutions having downgraded their forecasts for 2013 in recent weeks. "It will have to be seen if US corporate earnings report will manage to remain the main focus of traders or if the wrangling over extending the debt ceiling will increasingly overshadow and neutralise positive earnings reports."FTSE 100: AB Foods impresses; Rio disappointsAssociated British Foods made decent gains early on after strong retail and sugar sales buoyed encouraging growth in the 16 weeks to January 5th. Total revenues were up 10% year-on-year.Heading the other way was mining giant Rio Tinto after its CEO Tom Albanese stepped down following an announcement by the company that it expects to recognise a non-cash impairment charge of approximately $14bn in its 2012 full-year results. Real estate investment trust Hammerson gained after entering into a joint venture worth £1bn with Westfield to redevelop the retail centre of Croydon.Investment management group Aberdeen fell despite saying that assets under management rose 3% in is first quarter. The group did show an element of caution in its outlook, however, saying that while stock markets have begun strongly in the 2103, "we believe that uncertainty still persists and that further periods of volatility remain likely in the months ahead".Oil giant BP was subdued after yesterday's news that Islamist militants have kidnapped foreigners in a terrorist attack at one of its gas fields in Algeria. Overnight, it has been confirmed that two people have been killed in the attack.Home Retail jumps early onArgos and Homebase owner Home Retail rocketed this morning after lifting its profit guidance for the full year after a decent performance at Argos.Translation and communications software group SDL was in the red after saying that profits would fall short of market forecasts. Transport, logistics and support services firm Stobart was also lower after saying that full-year results will miss current market forecasts after a mixed third quarter.Dixons Retail was firmly lower despite reporting a 7% rise in like-for-like sales in the 12 weeks to January 5th.FTSE 100 - RisersAssociated British Foods (ABF) 1,625.00p +4.43%BT Group (BT.A) 247.60p +2.65%Old Mutual (OML) 185.00p +1.59%IMI (IMI) 1,139.00p +1.42%Tate & Lyle (TATE) 797.00p +1.08%ARM Holdings (ARM) 852.50p +1.07%Royal Bank of Scotland Group (RBS) 353.80p +1.06%Barclays (BARC) 295.55p +0.73%International Consolidated Airlines Group SA (CDI) (IAG) 204.40p +0.69%AstraZeneca (AZN) 3,058.00p +0.69%FTSE 100 - FallersRio Tinto (RIO) 3,355.00p -2.98%Polymetal International (POLY) 1,077.00p -1.82%Aberdeen Asset Management (ADN) 384.60p -1.81%Xstrata (XTA) 1,127.00p -1.36%Glencore International (GLEN) 376.05p -1.10%Petrofac Ltd. (PFC) 1,678.00p -1.00%BHP Billiton (BLT) 2,057.00p -0.94%Kingfisher (KGF) 285.90p -0.87%Carnival (CCL) 2,498.00p -0.87%SSE (SSE) 1,425.00p -0.84%FTSE 250 - RisersHome Retail Group (HOME) 139.00p +14.40%Petropavlovsk (POG) 383.70p +3.59%Computacenter (CCC) 434.00p +3.33%Brown (N.) Group (BWNG) 376.40p +2.84%Daejan Holdings (DJAN) 2,990.00p +1.98%Dunelm Group (DNLM) 733.00p +1.88%Ocado Group (OCDO) 83.85p +1.70%Ted Baker (TED) 1,176.80p +1.54%Cable & Wireless Communications (CWC) 37.75p +1.48%Moneysupermarket.com Group (MONY) 173.50p +1.46%FTSE 250 - FallersNew World Resources A Shares (NWR) 296.10p -5.31%Dixons Retail (DXNS) 26.34p -2.84%SDL (SDL) 501.00p -2.34%Hochschild Mining (HOC) 442.00p -2.21%Stobart Group Ltd. (STOB) 93.10p -2.05%Domino Printing Sciences (DNO) 632.00p -1.86%Go-Ahead Group (GOG) 1,260.00p -1.64%Regus (RGU) 110.90p -1.51%Grainger (GRI) 124.30p -1.51%IP Group (IPO) 124.70p -1.34%BC