Financial Conduct Authority chief executive Nikhil Rathi told Treasury Committee chair Dame Meg Hillier that the regulator will examine evidence of pre-Budget share moves in bank stocks under market abuse rules, after Bloomberg reported accurate details of planned bank tax changes before Chancellor John Healey stood up on 28 October.
Rathi's letter, published this week, said the Treasury and Cabinet Office are best placed to determine whether unlawful disclosure of inside information occurred. The FCA will review any evidence they supply and decide whether action under the Market Abuse Regulation is warranted. Hillier had asked whether political communications channels might have leaked market-sensitive fiscal choices.
Timeline that triggered scrutiny
Bank shares climbed on 27 October ahead of the Budget as traders digested wire reports that the restored bank corporation tax surcharge would not return to its previous 8 percent level, implying a lighter hit than feared. When Healey confirmed a lower surcharge on the day, prices remained elevated relative to the prior week, prompting questions about who held the information beforehand. The FCA does not investigate Budget politics as such, but MAR applies when price-sensitive fiscal details reach the market improperly.
Rathi stressed that parliamentary scrutiny remains the right tool for political accountability, adding that the FCA may intervene when discourse or poor information handling improperly moves securities. That framing keeps the door open to enforcement without preempting the Cabinet Office's leak inquiry.
What MAR enforcement could look like
Proving unlawful disclosure under MAR requires identifying who possessed precise fiscal parameters and whether they traded or tipped others. Regulators may request trading records from market makers active in FTSE bank lines during the narrow window. Civil penalties under MAR differ from criminal market-abuse prosecutions, but either route would alarm City compliance heads already managing Model Portfolio Service rebalance rules ahead of fiscal events.
Operational lessons for firms
Banks tightened embargo lists around the Budget, yet price action suggests information may have escaped traditional channels. Compliance officers are revisiting policies on economist notes shared with corporate-banking clients in the 24 hours before fiscal statements. For retail investors, the practical takeaway is that pre-announcement rallies in politically sensitive sectors now attract formal regulatory attention, not just parliamentary anecdotes. The FCA's willingness to engage Hillier signals that Whitehall information security and MAR compliance are linked problems after major fiscal set pieces.
Market-abuse teams at major brokerages said they would preserve chat logs from the 27–28 October window as a precaution. Whether those logs reveal anything beyond normal positioning is unknown; the regulator has not opened a public enforcement reference. Hillier's committee may still call Treasury officials to explain embargo procedures before the Commons returns.