Does a root domain get SEO power from its subdomains?

[ebebeb]

Hi there! I'd appreciate your help with the following case:

a) Current 10-year-old website (community) on root domain "example.com" (250,000 incoming quality-backlinks) will move to the new subdomain "newsub.example.com" (301 redirects to the new subdomain for all current subfolders)

b) A new website (shop) will launch on the root domain "example.com"

Question: Will the new website on "example.com" get SEO power from the old website on "newsub.example.com"?

SEO power = linkjuice/authority/trust/history/etc. from the 250,000 backlinks.

What I'm trying to achieve: Maintain the built-up SEO power for the root domain "example.com"

Thanks for sharing your thoughts on this!

P.S. Plenty has been written about subdomains inheriting from their root domains (so please don't share input on the subdomain vs. subfolder debate). But I can't find satisfactory info about the other way around (root domains inheriting from their subdomains), e.g. if wikia.com gets SEO power from its subdomains superman.wikia.com, starwars.wikia.com, etc.)

[OlegKorneitchouk]

I recommend you keep the site as is and just create a shop in a /shop/ subfolder on the main domain.

authority comes from external backlinks, if you move the main site to a subdomain (without redirects), traffic will drop and you'll have a ton of links to 404 pages, creating a giant mess.

if you do redirect to subdomain, then all of the authority will follow with it (except for links to the main root domain). you'll also need to be careful to not have any urls that overlap with old urls that you are now redirecting (again, high chance of mistakes).