Bill Greates

"Send $500,000 to an ally in co-op in one go."

- Official BTD6 description

 is a hidden achievement in BTD6, first added on Version TBA. It is achieved by sending $500,000 to another player in one go during Co-Op Mode. Because only 20% of a player's held cash can be sent at a time, they need to stockpile at least $2,500,000. Earning this achievement will reward 5 Cash Drops. This achievement will not be visible until it has been completed. The achievement will unlocked at the end of the next round, after the donation is done.

Summary
Accumulate a lot of money in Co-Op Mode and once at least $2,500,000 is reached then send money to any Co-Op partner. Maximum solo farming is required, and often can be earned the quickest with Monkeyopolis. Banana Central mixed with multiple BRFs also maximizes income gain.

Tips

 * You will likely be required to go to higher freeplay rounds to farm for this achievement. As such, ensure that you and your teammates network connections are good to avoid being disconnected on later rounds.
 * Have your team pass the money around. Let each person donate $500k+ in one ago so that everyone gets the achievement.
 * Attempt an Easy Standard game with you and your teammates using Benjamin. Immediately farm as much cash as you possibly can, but be sure to focus on defense to avoid losing on early rounds.

Trivia

 * This achievement's name is a reference to Bill Gates, one of the richest people in the world who often donates huge sums of money to charities around the world. In fact, Gates mostly does philanthropy work after departing from his Chairman status at Microsoft in 2014 and then detaching from its brand entirely in 2020.