RE: 2 Tiered System in the UK29 Oct 2025 23:45
Senator1, Where do you get your figures from?
Based on the closing prices for the last 12 months, I'd calculate the mean as c291p and the standard deviation as c52.5p, giving you a ±2𝜎 between c186p and c396p, whereas based on the closing prices for the 12 months immediately prior to the trading update on 20 October, I'd calculate the mean as c298p and the standard deviation as c52p, giving you a ±2𝜎 between c194p and c402p.
Alternatively, if you look at the closing prices for the 12 months immediately prior to the RNS on 07 October, I'd calculate the mean as c304p and the standard deviation as c54p, giving you a ±2𝜎 between c196p and c412p.
As can be seen, the ±2𝜎 range varies based on which data range you choose to pick but it's also a bit specious because, prior to 20 October, the closing share price never actually fell below 217p at any point during the 12 months prior, despite the -2𝜎 being below 200p throughout! Statistical analysis of share price movements may be appropriate if a company trades in line with expectations throughout the period in question (then it's not unreasonable to assume that, even if there are periodic peaks and troughs, the share price will generally revert to its normal line of trajectory over time) but I don't think it should be relied upon once a company starts issuing profit warnings and their ilk. E.g. one could argue that the entire data set from the trading update on 15 July onwards is now invalidated because if the market had been aware of the operational issues before the announcements in October it would have marked the share price down a lot sooner (I'm not suggesting any wrongdoing on BME's part) which in turn would have changed both the mean and the standard deviation.
Even if the share price does pass your 196p criterion I'm not sure that it should be read as a buy signal and I'm not aware of any charting tool that uses ±2𝜎 for that purpose. On the other hand, standard deviation (1𝜎) does form the basis for computing moving averages and Bollinger bands. Given the fact that 100% of the closing share prices for the 12 months immediately prior to 20 October exceeded 217p it does seem somewhat far feteched to suggest that 196p is the critical figure to look out for, simply because it happens to be two standard deviations (2𝜎) from the mean share price over the same period, especially if part of the data set has, arguably, become invalidated because the market was not fully cognisicant of all the relevant facts in real-time. I fully appreciate that it would be both impossible and impractical for BME to update the market in real-time but, nevertheless, the fact remains that if the market had been aware of the operational issues as they arose, rather than when they were disclosed/discovered, the share price during the period from 15 July would have likely been a lot different. It simply means that the data set is unreliable.