Some Wall Street firms are reevaluating policies for drug testing employees. Here's where the biggest banks stand on testing workers for marijuana use.

A Morgan Stanley spokesperson told Business Insider that the bank does not test employees or job applicants for marijuana use.

The spokesperson added that the policy has not changed in the last few years, despite the increasing support for marijuana legalization in the US.

Though a few Morgan Stanley alumni have decamped to the cannabis industry, the bank has not advised on or provided financing on any deals in the sector as of this month.

Citigroup is reevaluating its policy on screening job applicants for marijuana use as more Wall Street banks weigh whether to work with the industry, a representative confirmed to Business Insider.

The person pointed to the changing social climate around marijuana legalization as the reason. Thirty-three states now have laws allowing some form of legal access to marijuana.

The Citi representative confirmed to Business Insider that while Citi still tests all job applicants for marijuana use, it had held discussions over whether to change the policy in recent months.

Citi has also held talks in recent weeks about how closely it should work with cannabis companies or clients in other industries who want a loan to invest in the marijuana market, as Business Insider previously reported.

A spokesperson for JP Morgan Chase declined to comment to Business Insider regarding this story.

A document obtained by Business Insider shows that JP Morgan does urine test all of its supplier's employees, at the supplier's expense at a Substance Abuse Mental Health Service Administration (SAMHSA) certified site.

JPMorgan, however, is starting to make inroads into the cannabis industry. The bank provided financing to Altria Group for its purchase of a minority stake in Canadian pot producer Cronos Group last year.

Wells Fargo doesn't drug test as a condition of getting hired by the bank but has a zero tolerance policy for substances, a spokesperson told Business Insider.

"We have no tolerance for illegal drugs, including marijuana," the spokesperson said. "Our Drug Free Workplace Policy has remained consistent over the past several years in the midst of many state changes regarding legalizing marijuana (medical or recreational) and the company continues to recognize it as an illegal substance under federal law so it is prohibited in the workplace."

A spokesperson for Bank of America told Business Insider that the bank does not do pre-employment drug testing. The bank hasn't changed its policy recently.

Bank of America recently initiated coverage on a number of Canadian cannabis stocks, including Canopy Growth, Aurora Cannabis, Hexo Corp, and Cronos Group. The bank also provided financing to Constellation on the Corona maker's $4 billion purchase of an equity stake in Canadian marijuana cultivator Canopy growth.