Mastery

To unlock the Mastery Rank for missions you must get 3 stars on the mission, their are 4 stages of Mastery. Bronze, then silver, then gold, then platinum. Every stage rewards you except for platinum, which has no reward yet. (This means filling the platinum bar won't give you a reward. Filling your gold bar and unlocking to platinum does give you a reward.)

Bronze.
Reward for unlocking:

Silver.
Reward for unlocking:

Gold.
Reward for unlocking:

Platinum.
Reward for unlocking:

''Does Platinum still have no reward? I'm not even close to completing a Platinum mastery on any mission atm... Can anyone confirm this and post here with the results?''

If you asking filling the platina bar until full exp get reward then the answer is no. -zhi

Platinum still has no reward so its pointless to spend the time doing the platinum mastery