Diversifying NISA brokerage accounts between spouses

Hi all,

I am considering opening a NISA account for my spouse, who does not have it. I am on Rakuten Securities and I was wondering if there are any opinions on choosing a different brokerage for her specifically to minimize a risk of a brokerage going down.

As far as I understand in Japanese system if a brokerage goes down the assets will be transferred to a different brokerage (without triggering a selloff) and that is essentially it, so there should be no risk putting both our investments in the same brokerage.

I might, however, miss something and it might be better to diversify still for other reasons?

by IHateRemakes