Speculators and the Volcker Rule

No English language definitions of speculation or the Volcker Rule exist. 
Buying and selling things when the writer dislikes the deal is speculation.  Buying and selling things when the writer likes the deal is prudent investing.  Like and dislike is personal and subjective.  Deals that loose money are likely to be dubbed speculative.  Deals in foreign currency, derivatives, sub prime mortgages and short sales are more likely to be called speculative than deal in stocks and bonds. 
   The Volcker Rule forbids some bank trading in the stock market and other places.  It permits some bank trading.  The differences between forbidden and permitted trading have never been spelled out in words. Some say that the Volcker Rule prohibits speculation.