"Retirement fund" is the term used by the Strike Team to refer to the savings they accrued through illegal schemes.
When Vic Mackey asks Shane to borrow some money fromt he fund to pay Gordie Liman, Shane refuses to and explains that he invested the money in some stock options, hoping to maximize it. However, Mackey blasted him for not consulting with him. Later, after they deposited another sum on the fund, Mackey asked all three for their keys to the trunk telling them he couldn't trust them anymore. Reluctantly, all of them gave Mackey the keys. After some time of keeping them shut, Vic agreed to return each of them their keys.
Before Season 3Edit
After the Strike Team robbed the Armenian Money Train, they stashed all the money they got in their trunk. Shane rented a storage place under the alias of "Cletus Van Damme" where they stored the trunk with the money. They then agreed to not use the money for several months until the case went cold.
When they realized that Shane's alias might implicate him, they moved the money to another storage under the alias of "Mr. London". As they were checking it, the facility manager, Albert Krieg, came by and greeted them. Vic then told Shane to change the padlocks for the storage in case Albert wanted to check the place.