UK markets opened tentatively on Friday morning, making only slight gains as investors digested inflation data in China and economic stimulus in Japan.Chinese inflation rose to 2.5% in December as cold weather resulted to a increase in food prices. "While the figure remains well below the inflation target of 4%, it has raised concerns that it could lead to a tightening of monetary policy in the first half of this year," according to market analyst Craig Erlam from Alpari."The loosening of monetary policy appears to have been largely responsible for the improvement witnessed in the economy in the fourth quarter," he said.As such, mining stocks in London were firmly out of favour this morning on concerns over Chinese growth, with BHP Billiton, Rio Tinto and Anglo American registering losses.In other news, Japan's newly-elected Prime Minister Shinzo Abe unveiled a 10.3tn-yen stimulus package, aimed at raising economic growth by 2% and creating 600,000 new jobs.Markus Huber, the head of German HNW trading at ETX Capital, said: "No doubt the news out of Japan is encouraging, however at the same time it needs to be seen if indeed these measure will also have a positive long term impact on the economy or just provide a short-term boost, and in the end just lead to a worsening of the already dire financial situation in Japan."Tullow disappoints; IAG flying high after upgradeOil giant Tullow was under the weather after achieving average working interest production of 79,200 barrels of oil per day (bopd) in 2012, below the forecast range of 80,000-84,000 bopped. The group also revealed that exploration write-offs more than doubled last year due to a number of unsuccessful drilling activities and licence relinquishments. British Airways and Iberia owner IAG was in demand this morning after UBS upgraded the stock from 'neutral' to 'buy', following its underperformance against other European airline shares under the broker's coverage. "We think that IAG could be the laggard most likely to outperform in 2013 should it achieve the concessions the company wants from Iberia staff," the broker said.Financial stocks were performing well this morning with banking peers RBS, Barclays and Lloyds among the highest risers. Asset manager Schroders was higher after Credit Suisse upgraded the stock to 'neutral', while insurance giant Aviva was lifted by an upgrade by Citigroup to 'buy'.High Street giant Marks & Spencer was lower, extending losses from yesterday after its third-quarter sales disappointed the market. The stock was taken down a peg by HSBC this morning, which downgraded its recommendation for the shares to 'neutral'.On the FTSE 250, comparison website Moneysupermarket.com surged after saying that adjusted revenue is expected to have risen by 15% to £204.5m last year. Adjusted EBITDA is forecast to have risen 26% to £66m.
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