While stacking up cash is part of the American dream, carrying those stacks around could actually land you in legal trouble. Despite being the grease that keeps the wheel turning, large sums of money, in cash, will raise the ire of law enforcement. And while having stacks of cash is not illegal, it can result in unwanted police attention, seizure of the cash, and even arrest if evidence of a crime is found.
Generally, individuals do not carry around thousands of dollars in cash because that much cash is bulky and the modern banking and credit industry has made it much more simple to have access to that sort of money via credit cards and mobile banking.
However, because of the modern banking laws which require certain types of transactions be reported, criminals that receive large sums of cash, such as drug dealers, tend to avoid putting money in the bank. As such, when law enforcement officers find large stacks of cash on an individual, there is a presumption that the cash is meant for an illegal purpose, and can be used as the basis for a more in-depth search of your person, property, vehicle or home.