Anyone using Reuters Datalink ??

[rjay]

I'm a subscriber to Reuters Datalink and have just discovered that the open prices on the FTSE 100 index are always the same as the previous days close, from late 1999 to date. Before that, the open is different from the previous close.

I sent an email to customer support who said that there was no opening price on the FTSE100, from that date due to a change at the LSE.

Anyone else noticed ? Are they correct about the FTSE opening price ?

 

[RichardDale]

This is typical of an index whose constituents has a staggered open.

For example, let's take an index that has 50 constituents. Each group "opens" at a different time. Let's say each group is made up of 10 securities, and the opening time is staggered by two minutes each.

So we now have 5 groups of 10 stocks, which open at 10:00, 10:02, 10:04, 10:06 and 10:08.

Now going back to our index... where is the open? At 10:00 when only 10 stocks are trading? That's known as the first 'tick' of the chart. But is it really valid given that only 10 out of 50 constituent stocks are trading?

Is it at 10:08 after all stocks are open for trading?

This is something the index creator needs to define. In the absence of them defining a methodology for the opening price, all you have left is yesterday's close or a guess.

Cheers,
Richard.