A little guide to mod your money over 16 million.
1. Take in note the amount of money you have in game (i.e. 2850 money)
2. Transfer the ASSASSINSCREED3SAVEGAME1A to your computer.
3. Open it with Horizon/Modio and extract it to your computer.
4. Open the save game with an Hex Editor (I used Hex Workshop).
5. Convert the amount of money into Hex (2850 -> 0B22).
6. Flip the byte (0B22 will be 220B).
7. Now search for 220B. You should find one.
8. Change the bytes to FFFF (FFFF -> 65554 money).
9. Save, rehash, and resign.
10. DELETE the ASSASSINSCREED3SAVEGAME1B save game from your hard drive.
11. Check if it worked, it is possible that your Xbox freezes then you need to get more money.
12. If it worked go in to your game and get over 66000 of money (i.e. 66258 money). Steal some.
13. Convert money (66258 -> 0102D2).
14. Flip 0102D2 to D20102 to D20201 (Place the last two digits in front of it, then flip the fourth with the six). Find it and change it to FFFFFF.
15. Save, rehash, and resign.
16. DELETE the ASSASSINSCREED3SAVEGAME1B save game from your hard drive.
17. Check if it worked.
Here are 2 starter saves over 16 million money. I made 2 saves because you lose your money after you become connor.
The first is 3% (did 1 mission) done because i needed to steal money of people.
The second is after you completed the mission with desmond climing to the rooftop of a building.
Delete save B, Rehash and Resign with your IDs and play
If you want to mod your save its the same method as Revelations
Also thanks Ranger99 i modded his save.