Luckily there's an exceptional cast capable of selling the gravity of the circumstance, which is difficult to convey, given that there are no explosions or immediately life-threatening moves.  That cast includes Jeremy Irons, Zachary Quinto, Staney Tucci, and Demi Moore.

The trailer debuted at Yahoo! Movies.

"Something big is going down."  Good tagline, getting the point across while also keeping things simple and dramatic. 

According to Investopedia, a margin call is, "A broker's demand on an investor using margin to deposit additional money or securities so that the margin account is brought up to the minimum maintenance margin. Margin calls occur when a you account value depresses to a value calculated by the broker's particular formula."  Just saying.

Margin Call also stars Simon Baker, Kevin Spacey, Penn Badgley, Paul Bettany, and Mary McDonnell, who you'll remember fondly from Battlestar Galactica.  The film is written and directed by J.C. Chandor, making his feature debut after directing the 2004 short Despacito, starring Will Arnett.

The film hits theaters on October 21st.