If you have lost a large amount of money in an investment, you know how awful it feels. It is stressful, frustrating, and worse yet, it can be financially ruinous. It is also right that the responsible party is held accountable. However, under U.S. federal securities law and FINRA regulations, investors cannot hold brokers legally liable simply because they lost money. In order to prevail in an investment fraud lawsuit or FINRA arbitration cases, an investor must be able to assert a viable ‘cause of action’. In the simplest of terms, an investor must be able to prove that their financial representative committed fraud or acted in a negligent manner and that there is a connection between the fraud or negligence and the investor’s financial losses. There certainly some cases in which financial advisor fraud or stockbroker negligence is clear and obvious. However, most investment fraud claims are highly complex. To prove fraud or negligence, investors should work with an experienced attorney who can help them carefully assemble all of the documents, records, and evidence together into a compelling, persuasive legal case.