California will need to provide banks and credit unions with significant details about licensed marijuana businesses if the state wants to encourage financial institutions to serve the industry when recreational sales start next year, two bank executives told a state treasurer-appointed panel Friday.

Sundie Seefried is CEO of Denver-based Partner Colorado Credit Union, whose Safe Harbor Private Banking division serves 130 marijuana-related businesses with deposits of $85 million. Julie Robinson is senior vice president and compliance risk manager for River City Bank of Sacramento, which does not serve the industry and has not made any announcements about doing so after Jan. 1.

Although they represent different perspectives, both bankers suggested to the treasurer’s Cannabis Working Group six things the state can do to entice banks to accept marijuana businesses and ease concerns about federal regulators:

Put more money into law enforcement to discourage out-of-state transportation and criminal activity.

The U.S. Department of Justice’s “Cole memo” offers bankers some protections for serving marijuana businesses in states where they operate legally. But they don’t “go far enough,” Robinson said, as banks still need to reasonably believe that customers’ products aren’t falling into the hands of minors or being moved across state lines.

“It becomes our responsibility then to make onerous law enforcement-types of decisions that we are not equipped to make,” Robinson said.

Maintain a registry of licensees that banks can regularly access to ensure their customers have legitimate operations.

Third-party vendors are increasingly offering verification services. But federal regulators want assurances that bankers have taken steps themselves to know what their clients are doing.

“There is no silver bullet to banking this industry,” said Seefried. “Knowing your clients sufficiently to know that they are not involved in an illicit business, generating any criminal dollar and utilizing a financial institution to launder such money requires substantial personal attention to relationships.”

Provide a confidential “alert” system so banks and credit unions known when a customer’s license is in jeopardy of being suspended or has been revoked.

Ask marijuana-related businesses to identify their financial institutions when they apply for licenses so the state can monitor whether businesses are using multiple banks, a possible tip off to illicit activity, Robinson said.

Give banks unredacted copies of license applications and supporting documents.

Publish gross sales and lists of products sold by dispensaries in the state. Guidance issued to banks by the U.S. Department of the Treasury’s Financial Crimes Enforcement Network requires that marijuana banking customers demonstrate proceeds commensurate with other dispensaries in the area. Banks have no way to demonstrate that, Robinson said. “I am absolutely certain that if I walked into a dispensary that I don’t bank tomorrow and ask them for their revenues they would just laugh,” she said.

Access to banking remains a key hurdle for legalized marijuana operations as financial institutions remain fearful of dealing in a trade that’s still considered illegal at the federal level.

Some credit unions in Colorado, Washington and other legalized states do provide services to marijuana businesses. Other banks do so quietly. But many in the industry still operate largely—and dangerously—in cash.

California Treasurer John Chiang said the working group will discuss the idea of a public bank for marijuana businesses at its next meeting. In December, Chiang said he did not support the idea of creating a state bank solely to serve marijuana customers.