City Takeover uses bribery to lower the money cost of every remaining gang upgrade. Buy it early in the Swindler branch if you plan to fill the board.
City Takeover is entry 5 of 13 in the Swindler branch, one of the three branches (Ringleader, Insider and Swindler) on the Rooks' 39-upgrade board. It is bought with money and materials, not skill points: £10,000, 50 Silk, 50 Chemicals. Before City Takeover unlocks you need Black Market Ties.