Notice about London Stock Exchange Quote Irregularities

Thursday, Jan 04 2018 by

In the last 2 weeks there have been numerous price quote irregularities on London Stock Exchange listed stocks - sometimes with quotes incorrect by large margins - especially at the beginning of the day. We, and many brokers, have been publishing these irregularities which has caused concern amongst private investors.

I wanted to write a quick note to explain:

  1. Explain why this has been happening.
  2. Explain what we, and others upstream, are doing to improve matters. 
  3. Give some timeframes for likely resolution.
  4. Ask for your patience while we work these issues through.

Why has this been happening? The London Stock Exchange, in order to comply with new sweeping European MIFID II Regulations that have just come into effect, has split the price reporting of every London listed share price into two separate data feeds. One for "on-book" trades, and one for "off-book/off-exchange" (over the counter) trades. For what historically have always been unique, singular instruments, they have created 2 separate ids and 2 separate channels for every share price quote.

This has caused all kinds of havoc amongst data vendors. At Stockopedia, we were suddenly forced, at very short notice, to accept 2 data feeds (via Thomson Reuters) for every London listed stock and attempt to merge them.

The problem is that the off-book trade data is extremely noisy, and often poorly reported. Some stocks trade off-book in foreign currencies. For example JPEL Private Equity (LON:JPEL) is a share that a lot of subscribers own, and it's flipping between quotes in GBP and USD - but also between minor and major currency units. This is not ideal to say the least as it's messing up standard calculations of things like change on day / percent change on day etc. We're reacting as we can. What's more, sometimes we're receiving the correct price, but in the wrong currency or wrong currency unit.

MIFID II aims to improve the 'transparency' of trade reporting but it seems that this interpretation of the rules is making it much harder for the lay investor to gain clarity on what is going on.

What are we doing? We have been consolidating the two feeds into a single consolidated quote, but the data inconsistencies have been hard to completely clear up. Due to the ephemeral nature of price quotes, it's been hard to isolate whether the issues are coming from the exchange or Thomson Reuters, but we're working with all parties to resolve the issue. We're something of an innocent bystander trying to mop up the instabilities created upstream.

How long till a permanent fix? We're continuing to build, improve and debug our own fixes. I anticipate quotes will be much more robust within 24 hoursI have also now been informed by the Head of Product at Thomson Reuters, that they are going to be consolidating all the off-book and on-book London trades into a single quote instrument again. With any luck we'll have this within about two weeks which should further stabilise quotes. 

Thanks for your patience while we resolve these issues. If you do see a quote that looks unusual - try and verify it on the London Stock Exchange website. Reporting issues to us will also speed up our debugging of the problem. 

If you do see issues, please do log them on this thread. 

Filed Under: London Stock Exchange,


As per our Terms of Use, Stockopedia is a financial news & data site, discussion forum and content aggregator. Our site should be used for educational & informational purposes only. We do not provide investment advice, recommendations or views as to whether an investment or strategy is suited to the investment needs of a specific individual. You should make your own decisions and seek independent professional advice before doing so. Remember: Shares can go down as well as up. Past performance is not a guide to future performance & investors may not get back the amount invested.

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33 Comments on this Announcement show/hide all

Edward Croft 4th Jan 14 of 33

In reply to Warranstar, post #13

We will definitely have it sorted out soon. It's just a matter of time. I'm hopeful that the updates we push in the next 24-48 hours will create a lot more stability, but if that fails, I'm hopeful that Thomson Reuters will when they catch up.

Such a nuisance.

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LinnetIC 4th Jan 15 of 33

Hi Ed, Many thanks for explaining the issue, and what you are doing with your team to sort it out. It seems that Mifid II is essentially fixing an issue that wasn't broken in the first place! Good luck with it all.

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James RH 4th Jan 16 of 33

In reply to herbie47, post #9


Are you referring to the prices in your portfolio or stock page? If portfolio, you can change it to show the bid price rather than last trade price - go to the 'you' button at the top right of the screen, and choose site settings. Last one gives you the option to change it.

I prefer the bid price as this should technically be what my portfolio is worth.


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herbie47 4th Jan 17 of 33

In reply to James RH, post #16

Stockpage. On the stockpage it showed YouGov (LON:YOU) 360p +8.8%. Yes in portfolio I have bid price but on fantasy fund you can't have that, so it's going up and down all day long just because of last trade. But in portfolio it is still showing up 8.8% but bid has not changed, unless you know what the bid price was all the time it's difficult to know what is happening with Stockopedia prices.

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Nick Ray 4th Jan 18 of 33

As I understand it (which is only vaguely), the goals behind the new reporting rules are that all off-book trades (by organisations over a certain size) must now be reported. Those organisations doing such trades are called "Systematic Internalizers" (SI) and the idea is that any market participant can see everything that is going on.

As part of that, someone has to take all these trades from various places and glue them together. The LSE are doing this through "TRADEcho" which provides an "Approved Publication Arrangement" (APA). (The whole thing is a maze of abbreviations. Some explanation and diagrams here.)

My guess is that during these early stages, some of the SI organisations are feeding incorrectly formatted data into the system (wrong currency or currency unit, etc) and so whenever one of the rogue SIs does a trade it appears in the feed and confuses everyone downstream. (Even in the good old days though, Yahoo would report several stocks with out-by-100 errors so this is not completely new.)

Hopefully there is some mechanism in the system to pick up anomalous pricing and send warnings back to the SI who sent it so that gradually the bugs in the providers' code gets fixed up.

What I don't quite understand though, is why LSE do not merge their on-book trades with the off-book trades into a single feed.  Because it seems that everyone downstream is now having to implement that merge functionality separately. Lots of overlap and opportunities to get things wrong.

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TimL 4th Jan 19 of 33

Thanks Ed for the announcement and explanation. It's particularly impacting myself due to the erratic nature of the portfolio valuation. Tavistock is one stock whose share price has been ofter erroneous for a while. Keystone Law went public in November but still is not making it into the portfolio entries. I currently refer to ADVFN for share prices. I do wish to clarify that I have found the Stockopedia product very useful, and use it on a daily basis.

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Edward Croft 4th Jan 20 of 33

In reply to Nick Ray, post #18

What I don't quite understand though, is why LSE do not merge their on-book trades with the off-book trades into a single feed.  Because it seems that everyone downstream is now having to implement that merge functionality separately. Lots of overlap and opportunities to get things wrong.

Yes - nobody can understand why there isn't a single feed.  These are single instruments... one SEDOL/ISIN... they deserve a single quote feed.... but nope, we've got the Tradecho feed plus the old LSE feed.

At least TR are now consolidating all of it again in a single .L RIC (reuters instrument code).  

At the moment though, we've been having to merge the newly created .TRE (Tradecho) RICs with the old .L RICs - 2 feeds and too much can go wrong. 

I can only apologise.  Nobody thinks about private investors (in my opinion)... too much done for the benefit of the big organisations.  What people need is clarity. 

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traderp 4th Jan 21 of 33


Thanks for taking the time to give an explanation on this and what is being done to rectify it. It is a sign of great customer service that you have been proactive in detailing what is going on and how it is being resolved.

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cmorgan 4th Jan 22 of 33

"Nobody thinks about private investors " - I think you have hit the nail on the head although I question that anything about MIFID is to anyone's advantage (other than techies and lawyers). For instance having to pay separately for research has restricted the research available to investors of all stripes which clearly does nothing for market efficiency/price discovery. MIFID as a whole, coming on top of RDR, is / will be driving investors towards passives in turn making the market less efficient and the increased costs resulting from MIFID/RDR are denying advice to those who most need it. While intentions may be good the result is a horse designed by committee, ie a camel. I feel for you Ed!

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prem14 4th Jan 23 of 33

Thanks for the info - much appreciated. Fyi ,  stock price , market cap etc of  Fusion Antibodies (LON:FAB) are way out of order. It can't possibly be a billion pound business currently.

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jules2k6 4th Jan 24 of 33

Thak you for the explanation Ed

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Edward Croft 5th Jan 25 of 33

We put in some patches overnight which have hopefully solved the vast majority of the bad quotes some have experienced.

If you do experience an issue - please do use the green button on the bottom right of the site and let us know. 

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Fangorn 5th Jan 26 of 33

"This has caused all kinds of havoc amongst data vendors. At Stockopedia, we were suddenly forced, at very short notice, to accept 2 data feeds (via Thomson Reuters) for every London listed stock and attempt to merge them. "

Ah one of the unintended consequences of further EU meddling!
Mifid 2 is yet more regulatory burden and will cement Europe's place as the most over regulated, protectionist and anti competitive continent!! Jolly good show!

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Warranstar 5th Jan 27 of 33

For me today, the daily discrepancy between my portfolio value change as calculated by Stockopedia, and as calculated by my stockbrokers, is as bad as ever. I don't know who's share prices are a better reflection of reality. But, what I do know is that Stockopedia have explained the problem and have put in place measures to deal with it. I have no idea what my stockbrokers may, or may not be, doing about it, because they have not made any communication about it.

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whitmad 5th Jan 28 of 33

In reply to Fangorn, post #26

Financial services are not over-regulated, they are inefficiently and ineffectively regulated. Having spent a large part of my career working in investment banks and seen how they operate I have absolutely no trust in the financial services industry. Poor regulation is at least partly a result of excessive political influence by these organisations circumventing and hamstringing regulation, In this particular case, do you you think it is entirely an accidental side-effect that it adversely effects the private investor?

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Fangorn 5th Jan 29 of 33

In reply to whitmad, post #28

"Financial services are not over-regulated, they are inefficiently and ineffectively regulated."

Horses for course really.

Inefficiently regulated implies both badly regulated & over regulated! If it was"efficient" then it wouldn't be considered over regulated surely. It would be deemed fit for purpose.

Don't dispute that said regulation is inefficient however - such a conclusion is drawn from a similar career experience in financial services- unlike you however not solely Investment Banking side but both IB,IDB and AM - back, middle and front office. Quite an eye opener.

Much of the regulatory problems do indeed result from piss poor regulatory oversight - under the previous Labour Govt. It is also why we had the financial crisis due to lax regulation by Gordon Brown - but Mifid 2 is taking things far too far.

I doubt Mifid 2 will improve the lot of the individual private investor either.

But time will tell.

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Lucas 5th Jan 30 of 33


thanks for the background.

Could you please elaborate on the current impact of this situation on Stock Ranks? Are Stock Ranks affected in any way or are they relying only on end of day prices which are fine?


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Edward Croft 6th Jan 31 of 33

In reply to Lucas, post #30

Lucas - StockRanks should be unaffected. We are using the official close price for valuation which is in the primary quote currency.

I'm 90% sure that our current quotes fix is working - we had no complaints yesterday - but due to further changes likely from our upstream quote vendor there might be some more turbulence.

If anyone sees an issue - please do report it.

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Lucas 6th Jan 32 of 33

In reply to Edward Croft, post #31

thanks Ed. The Stock Ranks point is very important - glad they are not affected!

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fred flintstone 9th Jan 33 of 33

I am unable to comment except that it confirms my view that the private investor is always one step behind the big players and that we are only allowed to play to help pay expenses !

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About Edward Croft

Edward Croft

CEO at Stockopedia where I weave code, prose and investing strategies to help investors beat the stock markets. I've a background in the City and asset management but now am more interested in building great stock selection tools for the use of investors online.   Traditionally investors online have had very poor access to the best statistics, analytics and strategies for the stock market and our aim is to set that straight.  High Quality fundamental information has been prohibitively expensive in the past and often annoyingly dull. People these days don't just want to know the PE Ratio and look at a balance sheet. They expect a layer of interpretation over data, signal from noise and the ability to know at a glance whether a stock is worth investigating or not. All this is possible using great design and the insights gleaned from quantitative research.  Stockopedia is where we try to make it happen ! more »


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