Or, you might just want to slog through annoying practice questions, like this:

If your investor sells 1,000 ABC short @37, makes the required Reg T deposit, and then sees that ABC is trading for $18, what is true of the equity in the account?

A. the equity is unchanged

B. the equity is below the minimum maintenance requirement

C. the equity has decreased by $19,000

D. the equity in the account is $37,500

EXPLANATION: whenever someone sells stock short, he wants the stock price to drop. Since ABC does drop, you know that A and B can't be right. The equity has certainly

*changed*even if you aren't sure how. And, since the stock went the correct direction, the equity is improved not "below the minimum maintenance requirement." Do this type of work

*before*you start calculating--knock things off your plate as soon as possible. Now, really, you could eliminate "C," since the equity has

*increased*, and then to check your work do this . . . add the $37,000 the investor receives on the sale plus 1/2 that amount ($18,500), which is the cash he puts down. His Credit - $55,500. Just subtract the current market value of $18,000 from that, and you get the correct answer of $37,500. The opening credit on a short sale is "half again as much" as the short sale. Subtract the market value of the stock from that, and you've figured the "investor's" equity.

ANSWER: D