Market manipulation is a persistent problem in financial markets despite tough regulation.
Market manipulation is done to mislead others and profit from their wrong investing decisions.
Pooling, Churning, Stock Bashing, Pump and Dump, Runs, Ramping are frequently types of market manipulation.
In the currency market, pooling is a persistent problem.
Read this blog post in which what the UK Chancellor of Exchequer wants to do about market manipulation and rigging.
Market spoofing and quote stuffing are new forms of market manipulations done by High Frequency Traders.