A number of businesses in the burgeoning U.S. cannabis industry are trying to enlist Wall Street's help. Some entrepreneurs see marijuana heading down the same path as Prohibition, which banned the manufacture, transportation and sale of alcohol from 1920 until it was repealed in 1933. "More and more people see the inevitability," said Brendan Kennedy, chief executive of the Seattle private equity firm Privateer Holdings, which targets cannabis-focused start-ups. "They see that the Berlin Wall of cannabis prohibition is going to come down."