What is Stock Loan Quasi-mortgage?

Legal Definition
A Stock loan quasi-mortgage is a form of securities lending that uses stocks, bonds, mutual funds, or other eligible securities as the effective guarantee for a personal credit line used for the purchase of a home, investment in real estate, or for some portion of either of these (e.g., short-term finance, downpayments). Stock loan quasi-mortgages are typically in the form of a simple credit line, with interest-only repayment terms.

Although margin-loan financing is the most well-known form of individual finance in the field of securities lending, the stock loan quasi-mortgage is substantially different. These loans are crafted as non-purpose credit in compliance with FRB Banking regulations, as opposed to margin loans which are "purpose credit". The key difference is that margin loan financing is intended for the purchase of stock, allowing the client to leverage the value of their holdings, while "non-purpose credit" is for any application other than the repurchase of marginable securities. Interest, however, may be deductible.

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.
-- Wikipedia