Following yesterday's big profit warning that saw its share price more than halve, sports media company Perform (PER) bounces back with a 14% rise to 205p.

Insurance giant RSA (RSA) dives 18.2% to 81.4p after yet another poortrading update implies that its dividend could be cut for the second time in a year. The chief executive officer also leaves with immediate effect, as we discuss in more detail here.

Serco (SRP) drops 1.3p to 437.2p after flagging one-off charges relating to contract issues in its healthcare arm. We look at the news in more detail here.

It's 'game-on' for mobile device chips designer ARM (ARM), which is buyingthe £6.2 million computer games graphics tech business Geomerics from IP manager Angle (AGL:AIM). ARM is been pushing deeper into computer gaming with its Mali chip and Geomerics' enhanced lighting technology looks a neat bolt-on, although the scale of a 5.5% jump in ARM shares to £10.26 is surprising. But this is more grim news for rival chip designer Imagination Technologies (IMG) for which computer graphics are still its biggest revenue and profits centre. Its shares plunge more than 8% to 155.3p, making it a truly disastrous week after its messy first-half results on Wednesday sparked a 20% collapse in its share price.

The UK’s second largest drug maker AstraZeneca (AZN) rises 2.2% to £35.36 on newsthat the FDA’s advisory committee has recommended dapagliflozin for treating type-2 diabetes ahead of a final approval decision by the regulator. It also reported positive resultsfrom its phase III study for its gout treatment, but there were side-effects.

Following some profit-taking on Thursday, fashion brand retailer SuperGroup (SGP) tacks on 30p at £12.86 as investors digest yesterday's interim results. The expansionist Superdry brand owner delivered a near-22% underlying taxable profits surge to £17.9 million which gives the running Shares Play of the Week positive momentum ahead of Christmas.

Fashion-to-home furnishings retailer firm Laura Ashley (ALY) loses 0.45% at 26.38p as a weak trading statementprompts profit downgrades. For the first 19 weeks of the second half, like-for-like sales waned by 0.7% while web-based growth was a rather anaemic 1%. Though full-year licensing income is forecast to fall 16%, Laura Ashley says some 'significant' new deals will boost profits next year.

Amara Mining (AMA:AIM) soars by 16.7% to 14p after reporting a very large resource increase at its Yaoure gold project in Cote d'Ivoire. It now has 6.3 million ounces of gold at the project. The vital test for the share price will be the results of a preliminary economic assessment on the asset, expected in early 2014.

The restatement of accounts sends Office2Office (OFF) down 19.4% to 29p as previous years' profit is now less than reported. We flagged the big risks surrounding the company in an article in April and the shares have subsequently fallen by 69%.

Vehicle transmissions technology play Torotrak (TRK:AIM) slumps 11.4% to 19.5p as it announces a £16 million placing at 18p to help fund the acquisition of the 80% it does not already own in flywheel specialist Flybrid. The Leyland company has agreed to pay up to £23 million for the stake with an initial £8 million on completion of the deal. We discuss the background to the transaction here.

Oil explorer and running Play of the Week Petroceltic (PCI:AIM) sinks 1.1% to 159p as it announces a delay to the second well in a two-well campaign in the Black Sea off the Romanian coast. The rig used for this drilling requires unscheduled and necessary maintenance with the well now scheduled for the end of the first quarter next year.

Specialist engineer Pressure Technologies (PRES:AIM) gains 3.7% to 422.5p on news of a strategic investment in gas transport specialist GTM Manufacturing. The company receives a 40% stake in return for providing a $4 million loan to GTM.

Software developer tiddler Imaginatik (IMTK:AIM) has wona two-year contract extension with a major US property and casualty insurance company. Its shares jump close on 11.5% to 0.1p, valuing the company at £2.84 million.

Video marketeer Rightster (RSTR:AIM) is under the cosh as investor enthusiasm cools. The shares fall 11% to 45.5p despite reportingnew content rights agreements earlier this month. This means the shares have lost 23% since joining the stockmarketlast month at 60p.

AIM-quoted oil play Victoria Oil & Gas (VOG:AIM) gains 14.5% to 1.18p after its long-running dispute with RSM Production Corporation over the Logbaba oilfield in Cameroon was resolved by the court in charge of the arbitration. The Secretariat of the International Chamber of Commerce decided that RSM did not automatically forfeit its stake in the licence as Victoria had argued but it must now pay $4.1 million if it is not to default on its interest.

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Issue Date: 13 Dec 2013