If you were shocked (shocked!) to discover last summer that the LIBOR market was being rigged, prepare to be flabbergasted: Regulators are investigating a number of global markets that appear to be subject to manipulation.

“The probe of Libor manipulation is proving to be the tip of the iceberg,” Bloomberg reports, noting that various regulators are investigating markets including:

• Foreign exchange trading in the U.K.

• Singapore’s version of LIBOR (which stands for London Interbank Offered Rate)

• Brent crude

What all these markets have in common is a feature whereby levels are set, at least in part, by prices submitted by traders using the “honor system” vs. actual verified trades.

Related: LIBOR Scandal Latest Sign of Financial System’s Rotten Core

As Henry Blodget and I discuss in the accompanying video, it should really surprise no one that traders would manipulate markets if given the opportunity because the motives to do so are so compelling. And while these markets may seem arcane, they do have real world impact: LIBOR is the global benchmark for interest rates, including those on mortgages and auto loans, and Brent Crude is the global benchmark for energy prices.

Related: Don’t Trust the Market? You’re Not Alone...For Good Reason

The lessons of these relevations are many faceted. First, they should serve to disabuse all of us of the notion that the Internet – or any other technology – has created a “level playing field” for retail investors; last week's story about Thomson Reuters (legally) selling investors access to breaking news before it's public is just the latest reminder the playing field is very much not level. Second, investors would be wise to assume, as a general rule of thumb, that markets are manipulated (vs. fair) and proceed accordingly.

The message here is not to avoid the markets altogether, but a plea to understand the crosscurrents before entering the shark-infested waters.

And as you’ll see in the accompanying video, there is one sure-fire way to wade into the pool and limit your exposure to the market’s machinations.

Related: Is the Market Rigged? Absolutely, Says Streettalk Advisors CEO

Aaron Task is the host of The Daily Ticker and Editor-in-Chief of Yahoo! Finance. You can follow him on Twitter at @aarontask or email him at [email protected]