Cannabis and Taxes: The Future of Compliance with Calvin Shannon from Bridge West CPAs and Nick Miller from Greenspoon Marder. Bridge West CPAs, where Calvin Shannon is principal, is one of the first accounting firms in the world to focus solely on the cannabis and hemp industries. Since 2009, the practice has expanded to more than 400 cannabis and hemp clients nationwide. Greenspoon Marder is a national full-service business law firm with over 200 attorneys and 26 locations across the United States. Nick Richards is a Partner in the Tax practice group at Greenspoon Marder LLP. He represents individuals and businesses in tax audits & trials, M&A, in managing tax debt, and he advises cannabis companies, owners, and investors regarding tax and regulatory compliance matters.