100% financing with securities back mortgage for primary home

[Paul Jump]

I’m failing to find a downside. Essentially you pledge 30% of the home purchase price in eligible securities. It makes it so that you don’t need to liquidate for a 20% cash down payment. The only downside I can think of is that if the securities value decreased below the 30% threshold, you’d need to re-up. Am I ready this right? Anyone have experience with a program like this?

Here is an example program by BOA: https://fafpf.files.wordpress.com/2011/10/mortgage100andparentpower0911.pdf

Here is a WSJ article explaining: http://www.wsj.com/articles/selling-stocks-to-buy-a-home-how-to-do-it-right-1445441711

TBH feels like a loophole for the wealthy.