Increase in Number of Stocks in GTR1

Using GTR1 to count stocks, there was a substantial increase in the number of stocks about the start of COVID. It was a rapid rise, but not all at one day/month. Does anyone know what caused the rapid increase?

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One could probably take a look at styp.a & perform the count on that variable. That’d show where the increase in total equities occurred by security type.

The styp.a codes are described by the following …

Share Type - First Digit Share Type - Second Digit
1 Ordinary Common Shares 0 Securities Which Have Not Been Further Defined
2 Certificates, Americus Trust Components* 1 Securities Which Need Not Be Further Defined
3 ADRs (American Depositary Receipts) 2 Companies Incorporated Outside The U.S
4 SBIs (Shares Of Beneficial Interest) 3 Americus Trust Components*, Exchange Traded Funds**
7 Units, Exchange Traded Funds** 4 Closed-End Funds and Unit Investment Trusts
5 Closed-End Fund Companies Incorporated Outside The US
6 US-incorporated SPAC
7 Foreign-incorporated SPAC
8 REIT’s (Real Estate Investment Trusts)

One possibility is that there were a lot of SPACs issued at about that time due to the ‘SPAC boom’ (typically styp.a of 16 or less likely 17) & if so that increase should be working its way out of the system soon-ish (as the typical 2 year life of an SPAC would have or be about to expire). More here - Message: MI Board Search. (Thanks for the caching in datahelper demonstrated here!)

Another option would be to explore the sector (sector.s) & industry codes (indc.s) & see where there was an increase? That’d be a more involved parse though.

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Yes, an unexpected increase during the pandemic. The increase was roughly linear from August 2020 to January 2022: about a 15% increase over 16 months. (Active increased more because of all of the new ETFs.)

step0: [Security Type; lag=1 days] == 10,11,12,18,30,31,48
step1: [daily SI-adjusted Price; share_lag=1 days; quote_lag=1 days] > 0
step2: styp.a = param0
linkToTheScreen

Counts of stocks passing each step:

Date Active step0 step1
20080528 6955 5402 5305
20120620 6751 4700 4578
20200828 7647 4700 4454
20211227 9265 5400 5178
20221012 9579 5437 5238
increase 21% 15% 16% from 20200828 to 20211227

From 20200828 to 20211227, most of the new listings were in styp.a 11:

styp.a increase 20211227 20200828
11 472 3929 3457
12 199 645 446
31 55 389 334

change = IPOs + stypChanges - delistings

The styp changes may have been SPACs converting to ordinary stocks. stypChanges had an unusual spike in 2021. The number of IPOs spiked higher at the same time. And there were fewer delistings. Net effect was more ordinary stocks.

SIP stocks with styp.a=11!12:
change = IPOs + stypChanges - delistings
From 20201029 to 20211029: 554 = 304 + 450 - 200
From 20181029 to 20191030: -32 = 149 + 232 - 413

links:
stypChange
IPOs
SIPstocks1112
Excluding SPACs from GTR1 Backtests discusses changes in styp.a

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