The stock loan quasi-mortgage is not a mortgage in the purest sense, but rather an asset-based formed of financing that allows borrowers to tap their portfolios without having to liquidate them.
Unlike "non-recourse stock loans" which have been dismantled and regulated out of existence by lawmakers in the post-financial crisis era, the stock loan quasi-mortgage programs of today are handled entirely by and through fully licensed and regulated brokerages that are members of the Financial Industry Regulatory Authority (FINRA) and banks with transparent and audited financials.
A stock-loan quasi-mortgage can be used to purchase a residential or commercial property outright, and can mean greatly reduced payments over time.
Since most of these securities-type credit lines close very quickly (two weeks or fewer on average) they can be the perfect solution, and do not require the sale of stock that might trigger a taxable event.
Stock loan quasi-mortgages are sometimes used as "insurance" cash for those real estate investors who want to be able to pull out a check book on the spot and lock in a purchase at known rates and terms, without running into unreasonable bank limits or requirements.