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Market inefficiency meaning

What does Market inefficiency mean?
A situation where the market price of a security does not fully or promptly reflect publicly available information, so prices incorporate information imperfectly or with delay. The term is an economic description rather than a defined legal term; it is not defined in UK or Irish legislation or case law, but is used in securities regulation and litigation. Market inefficiency may arise from information asymmetry, defective or delayed disclosure, illiquidity, high transaction costs, limited investor analysis, limits on arbitrage (e.g. short-selling constraints), or market abuse (insider dealing or manipulation). Legally, it informs: (i) disclosure, listing and prospectus duties (FSMA 2000; UK/EU Prospectus Regulation), (ii) market abuse regimes (UK MAR; EU MAR in Ireland), and (iii) issuer liability claims (FSMA ss.90 and 90A). In practice, parties use the concept on materiality, reliance and loss causation, often via event studies of price impact and price discovery; it bears on whether a misstatement or corrective disclosure would move the market and on quantum. Usage is broadly consistent across England & Wales, Scotland, Northern Ireland and Ireland. Regulators (FCA; Central Bank of Ireland) promote efficient price formation under MAR and MiFID II but do not define the term.
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NEWS
UK pensions reform: Pensions Investment Review and Pension Schemes Bill 2025: DC megafunds (25bn by 2030), DB surplus release and LGPS pooling to support productive finance

What was the background to the Pensions Investment Review and the two associated consultations on ‘Unlocking the UK pensions market for growth’ and ‘LGPS: Fit for the future’? The Review was set in motion by the new UK administration, aiming to channel more investment, lift returns for savers and cut inefficiency across the pensions landscape. It arrived amid worries that UK pension schemes, both DB and DC, were underexposed to domestic productive assets, including infrastructure and venture capital. Ministers observed that, relative to overseas counterparts, British funds allocated comparatively little to these areas, and that this position limited exposure to domestic growth opportunities. The exercise was also intended to look afresh at how the pensions ecosystem is organised overall, paying particular attention to workplace DC arrangements and the LGPS in particular. More broadly, the Review sat within a wider government drive to release capital to strengthen the home economy and to ensure the UK’s financial architecture advances long-term national goals such as the transition to net zero and levelling...

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PRACTICE NOTES
Challenging TMO4+ Grid Connection Outcomes in Great Britain: G2TWQ and Enduring Regime – NESO/DNO Complaints, CUSC ADR, Ofgem Determinations, Judicial Review and Contract Claims

For fuller commentary on the regulation, consenting and incentivisation of the net zero energy transition under the laws of England and Wales, see also: Collinson and Hockman on Energy Law: Regulating, Consenting and Incentivising the Energy Transition. That textbook contains in-depth treatment of the topics addressed in this Practice Note. What is TMO4+? ‘Target Model Option 4 +’ (TMO4+) is a significant suite of reforms endorsed by Ofgem in April 2025, amounting to a comprehensive reset of Great Britain’s electricity grid connection processes. The package was driven by the UK government’s climate commitments and by persistent inefficiency and delay in the existing connection process, which have created substantial obstacles to investment and the deployment of renewable energy. This section briefly outlines the TMO4+ measures, highlighting the contrast between the previous grid connection system and the arrangements introduced through TMO4+. It also flags the energy market participants most likely to be impacted by TMO4+ reforms. Background Pre‑TMO4+, the route to obtaining a grid connection to both the...

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