[RndTbl] NASDAQ has bit-limit bug
Hartmut W Sager
hwsager at marityme.net
Sun May 9 06:42:46 CDT 2021
This is even more intriguing than I first thought below, as the following
It turns out that, before the U.S. exchanges were decimalized in 2000,
there was already a prelude to a smaller increment, namely one-sixteenth
> In 1997, the US Congress passed the “Common Cents Stock Pricing Act;”
later that year, trading in sixteenths began.
I love the pun (as in "common sense") in the name of the act, too!
So, my thought of going from 4 decimal places to 3 would prevent the
retention of accurate records for 1997-2000, since 1/16 = 0.0625.
Hartmut W Sager - Tel +1-204-339-8331
On Sat, 8 May 2021 at 05:00, Hartmut W Sager <hwsager at marityme.net> wrote:
> Intriguing! Of course that so-called "compact format" (in the article) is
> a 32-bit unsigned integer, capped at 2^32-1. While going to 64-bit integer
> is a very clean solution (not the only one), interpreting the 32-bit
> integer as having 3 decimal digits would also preserve exact one-eighths
> (0.125) and result in a new cap of 10x the current cap.
> Hartmut W Sager - Tel +1-204-339-8331
> On Fri, 7 May 2021 at 12:34, Trevor Cordes <trevor at tecnopolis.ca> wrote:
>> Kind of funny. Computer nerds will instantly spot the (bit) reason for
>> the limitation in $$ amount.
>> What's interesting is they are still allowing 4 "cents" digits. I guess
>> it's a holdover from the fraction days where stocks were "10 1/8". I'm
>> pretty sure no broker lets you trade in anything less than a cent these
>> I wonder if their fix is to switch to 2 digit cents, or move to 64-bit
>> systems and storage. My guess is the former would be infinitely easier,
>> though you may lose some historical precision if you make the change
>> If they go 2-digit cents, Buffett can grow to $42M a share... which should
>> take a decade at least (depending on inflation levels). :-)
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