This is the lowest cost and least speculative investment strategy of the four methods.

FORBES: Investment Principle Matters to Principal

In particular, it may be difficult to determine whether principal risk has been retained because (i) the retention of such risk is necessary to provide intermediation and liquidity services for a relevant financial instrument or (ii) the position is part of a speculative trading strategy designed to realize profits from price movements in retained principal risk.

FORBES: Volcker Rule Trumps Euro Euphoria For Financal Sector Outlook

Even if you never show a profit, you can claim your losses if you can show you had good reason to believe you might make money--a chance for a substantial profit in a speculative venture is enough--and adjusted your strategy or quit the business when it didn't pan out.

FORBES: Investment Guide