Google market charts internally inconsistent?

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Sylvie
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Google market charts internally inconsistent?

Post by Sylvie » Tue Mar 24, 2020 3:09 pm

My apologies if this is either embarrassingly basic and/or if it's already been discussed to death. I'm trying to make sense of Google's market charts. The YTD return doesn't seem to match what the chart shows. E.g., say I look at the chart for FZROX, and switch it to YTD view. If I hover at the beginning of the chart, it says Jan 2, $11.42, and at the end, Mar 23, $7.74. But under the chart, the YTD return is -8.47%. Why isn't the YTD return the % difference between $11.42 and $7.74?

retired@50
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Re: Google market charts internally inconsistent?

Post by retired@50 » Tue Mar 24, 2020 3:52 pm

Sylvie wrote:
Tue Mar 24, 2020 3:09 pm
My apologies if this is either embarrassingly basic and/or if it's already been discussed to death. I'm trying to make sense of Google's market charts. The YTD return doesn't seem to match what the chart shows. E.g., say I look at the chart for FZROX, and switch it to YTD view. If I hover at the beginning of the chart, it says Jan 2, $11.42, and at the end, Mar 23, $7.74. But under the chart, the YTD return is -8.47%. Why isn't the YTD return the % difference between $11.42 and $7.74?
If I had to guess, I'd say that it's calculating only to the end of February, instead of to today's price. Just a guess.

Regards,
Boggle - a game from Parker Brothers. Bogle - investor, founder of Vanguard.

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Sylvie
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Re: Google market charts internally inconsistent?

Post by Sylvie » Tue Mar 24, 2020 8:26 pm

retired@50 wrote:
Tue Mar 24, 2020 3:52 pm

If I had to guess, I'd say that it's calculating only to the end of February, instead of to today's price. Just a guess.
Oh, interesting. At the end of Feb, the chart says that one was $10.38, which is still slightly off from the reported YTD's 8.47% decrease, but only by a bit. If those are both closing values, but the YTD measures from the Jan open to the Feb close, I bet that would do it.

Odd, though -- I wonder why they call it YTD, and have the values to keep that up to Date, but choose to calculate it based on the prior month's close. Is that just convention with YTD reporting? Maybe based on when day-to-day values were harder to come by or something?

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#Cruncher
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Re: Google market charts internally inconsistent?

Post by #Cruncher » Tue Mar 24, 2020 8:45 pm

Sylvie wrote:
Tue Mar 24, 2020 8:26 pm
At the end of Feb, the chart says that one was $10.38, which is still slightly off from the reported YTD's 8.47% decrease, but only by a bit. If those are both closing values, but the YTD measures from the Jan open to the Feb close, I bet that would do it.
The -8.47% "YTD return" seems to be from 12/31/2019's $11.34 to 2/28/2020's $10.38. (You can see the $11.34 for 12/31 by switching to "1 Year" view and sliding the cursor slowly over the graph near the end of 2019.)

It's lazy software design that the "YTD return" doesn't actually measure what it purports to.

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Sylvie
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Re: Google market charts internally inconsistent?

Post by Sylvie » Tue Mar 24, 2020 8:59 pm

#Cruncher wrote:
Tue Mar 24, 2020 8:45 pm
The -8.47% "YTD return" seems to be from 12/31/2019's $11.34 to 2/28/2020's $10.38. (You can see the $11.34 for 12/31 by switching to "1 Year" view and sliding the cursor slowly over the graph near the end of 2019.)

It's lazy software design that the "YTD return" doesn't actually measure what it purports to.
Wow, thanks for figuring that out, and I'm amazed that they'd be that sloppy about it if there really is no good reason!

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Re: Google market charts internally inconsistent?

Post by onthecusp » Tue Mar 24, 2020 9:37 pm

Why would you expect them to start with the value at the end of the first day of the year? Starting with the previous year close seems like the correct choice to me.

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MP123
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Re: Google market charts internally inconsistent?

Post by MP123 » Tue Mar 24, 2020 9:50 pm

Interesting.

So for Google chart purposes YTD = year to end of last month?

It seems like they could just as easily calculate it to the current date.

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Sylvie
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Re: Google market charts internally inconsistent?

Post by Sylvie » Wed Mar 25, 2020 8:15 am

onthecusp wrote:
Tue Mar 24, 2020 9:37 pm
Why would you expect them to start with the value at the end of the first day of the year? Starting with the previous year close seems like the correct choice to me.
Sure, that makes sense -- I only looked at the value I did because it was the first value available on the YTD chart, which I'd expected would correspond to the YTD figure below the chart. But it wasn't the starting value I was questioning, but the ending one. I'd expected that Year To Date would have meant from the beginning of the year (or, sure, end of the prior year) to the most recent date, not the last day of the preceding month. The end of February is an especially long time ago in a month like this!

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Sylvie
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Re: Google market charts internally inconsistent?

Post by Sylvie » Wed Mar 25, 2020 8:16 am

MP123 wrote:
Tue Mar 24, 2020 9:50 pm
Interesting.

So for Google chart purposes YTD = year to end of last month?

It seems like they could just as easily calculate it to the current date.
Right? So much so that I wonder if it's actually a long-standing convention or something that made them decide to do it the way they're choosing to instead. I can't imagine they didn't think about it?

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Re: Google market charts internally inconsistent?

Post by glorat » Wed Mar 25, 2020 9:04 am

Funny his comes up... I wrote my own online graphing software to show returns and I have exactly the same "bug"

The reason for me is that it is too intensive to calculate daily values to be put into the graph... The graph resolution doesn't benefit from that granularity. So I simply compute monthly values and display those on the graph.

Pure speculation if Google did the same for the same reason

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onthecusp
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Re: Google market charts internally inconsistent?

Post by onthecusp » Wed Apr 01, 2020 4:17 pm

Sylvie wrote:
Wed Mar 25, 2020 8:15 am
onthecusp wrote:
Tue Mar 24, 2020 9:37 pm
Why would you expect them to start with the value at the end of the first day of the year? Starting with the previous year close seems like the correct choice to me.
Sure, that makes sense -- I only looked at the value I did because it was the first value available on the YTD chart, which I'd expected would correspond to the YTD figure below the chart. But it wasn't the starting value I was questioning, but the ending one. I'd expected that Year To Date would have meant from the beginning of the year (or, sure, end of the prior year) to the most recent date, not the last day of the preceding month. The end of February is an especially long time ago in a month like this!
I see, I only did half the analysis :oops: yes, their choice of end date is not consistent with "year to date."

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