Hawkeye realizes he's been running away from the fact that he's from a abusive family for his entire life. Upset at how immaturely he handles his problems, Hawkeye quits the Avengers and gives up crime fighting.
Tony, understanding what it's like to have the weight of the world on your shoulders, offers Hawkeye a job position in which Clint could test his unused skills(Clint went to college and earned a master's degree in business management, but never ran a business): being CEO and Chairman of a corporation that is a global leader in renewable energy, transportation, and infrastructure.
Hawkeye accepts, and renames the corporation from Michael Industries(the old CEO died) to BartonTech.
Clint, deciding to do something in his life besides put his life on the line, moves to Miami, where the headquarters of his company is located. Clint also decides to rekindle a long since forgotten relationship: talking to his sister, Laura Barton, again.
Laura and Clint stopped talking a long time ago because Laura disapproved of Clint crime-fighting. When she found out that crime-fighting was behind him, she gave Clint another chance.
Clint makes Laura Chief Financial Officer of his company, and the two work together perfectly for 6 months. During this time, Clint enjoys the benefits of being a newfound billionaire by living in a mansion, having his own private jet, yacht, and butler, and hosting his own expensive parties. Clint also believes that Miami has one of the lowest crime rates in the state due to having a strong police force and sound public educational system. In reality(and soon, Clint finds out the hard way), that Miami has one of the lowest crime rates due to the crimes being committed not being told....by the corrupt cops.
All of the corrupt cops are paid off by Fidel Meerez, a drug kingpin. He also happens to be Bartontech's chief public supporter(critics point to it as being a " near monopoly on infrastructure"). Clint finds out that the old CEO was killed off by Fidel's men and the corrupt cops made it look like natural causes because the old CEO no longer supported Fidel's money laundering operation. When Fidel found out that Clint wasn't going to allow money laundering either, he ordered hit men to assassinate Clint. Unfortunately, the hitmen got it wrong and assassinated clint's sister.
When Clint realizes noone is going to prosecute Fidel for his crimes, Clint decides(using his newfound wealth) to put on his classic costume, build a hawkcave, and produce trick arrows for only one reason: