A summer blockbuster brings us this week’s: Marketplace Money buzzword: Russell 2000.

Sounds like a movie title, but the Russell 2000 plays an important role in a world of prudent investment strategies.

It’s an important stock market index. Every year around this time, analysts change its “cast” of securities. That’s when some traders try to make a quick buck. They’ll buy shares they bet will be added to the index hoping to drive up the price.

But this year, analysts did things differently and added fewer stocks than expected. And those eager traders lost big-time! Just proves messing with the market can be murder.