It even managed to stall a divorce case. When one of the Coke heirs ended his marriage to his wife, she demanded some of his great-grandfather's (the founder of Coca-Cola) original notes as part of her settlement. The company had to get involved and put a stop to it out of fear the notes could contain information on the formula.
Only two Coke executives know it. Urban legend says they each only know half, but that's false--that part was invented for an old ad campaign.
How it is Kept Secret:
The original copy of the formula is kept in an undisclosed SunTrust Bank in Atlanta. To keep SunTrust on the side, Coke gave them some 48.3 million shares of stock as well as having executives from each company sit on the other's board of directors.
The company has policies surrounding the secret that range from the paranoid (the two executives who knew the formula could not fly on the same plane) to the bizarre (no one could view the formula without God, Jesus and Elvis present or something to that extent).
All of this is pointless in the end. Coca-Cola still derives some of its flavor from the coca plant; the same place that cocaine comes from. Due to the obvious drug related issues that would arise from importing lots of coca plant into America legally, only one company has government permission to do it. That company is Coca-Cola. So even if someone broke into the bank and managed to take the formula, they would never be able to produce an exact Coke rip-off.