Marijuana was officially legalized for recreational use in Colorado as of Jan. 1 2014, but being that it's still currently illegal both federally and in the 49 remaining states, the flow of funds associated with the sale of weed could cause headaches for financial institutions. Fortunately, the Department of Justice (DOJ) is expected to offer guidelines to financial institutions in a memo that the Wall Street Journal reports should be coming any day. But banks remain nervous that the guidelines do not go far enough to protect them.

Under current federal law, any bank institution caught accepting deposits from known drug dealers would be in violation of money-laundering laws. Deposits that are suspect require the bank involved to fill out suspicious activity reports. Financial firms are concerned that similar regulations could be used to charge them when dealing with Colorado-based marijuana sales.

The memo hopes to clarify the responsibilities of banks and financial firms in Colorado. Those close to the draft say that it emphasizes that federal enforcement will first go after marijuana sellers who use legitimate sale in Colorado as a front for other illegal activity, funneling it across state lines, or as part of a larger criminal drug empire, for example. The memo is expected to run parallel to another document that the DOJ released in 2013, in which it laid out eight prosecution priorities it would maintain as weed laws loosen across the United States.