Answer:
- 80
+ .7 = $56 margin price
- 80
- 56 = $24 in debt
- New
Low (NL) is [NL - $24 = .3NL] or, 7NL
= $24 = $34 ¼ = Lowest price to maintain
30%
- 34/80
= about 43%
- GE
has to decline by at least 57% to reduce Laura's
equity low enough to trigger a call.
This
is fairly simple, the only elegant piece is realizing
the purpose of the proportional math in the algebra:
to "tease out" the effect on the equity
vs. debt portion of the investment. This logic appears
ubiquitously throughout financial and investment models.