Margin trading is a practice in the financial markets where investors borrow funds from

their brokers to purchase securities$.$ This leverage allows investors to potentially

amplify their returns, but it also exposes them to increased risk, including the possibility

of receiving a margin call.

Scenario:

Consider the case of an investor who purchases $100$ shares of MSN common stock

on margin at R$70$ per share. The initial margin requirement set by the broker is $60\%,$

indicating that the investor must provide at least $60\%$ of the total value of the stock as

collateral. Additionally, the maintenance margin is set at $40\%,$ defining the minimum

level of equity that must be maintained in the position.

Objective:

The objective of this scenario is to analyze at what price level the investor would

receive a margin call, given the initial margin and maintenance margin requirements