Banks

Banks are unlockable bonuses, obtained with Perk Points and Quirk Points, that allow you to retain some percentage of your levels in Advanced Training, Beards Of Power (temporary levels), and Broken Time Machine when rebirthing.
Banked levels are lost when changing the difficulty level or starting a challenge.
Upon rebirth, banked Beard levels apply right away, without needing to first hit the E/M cap. However, banked Advanced Training levels do not have any effect until the AT menu is unlocked by completing Basic Training.
The details below apply to the Perks/Quirks for all three bank types, but each must be unlocked separately.
Bank Bonus 	Cost per level	Bonus per level	Cost for all levels	Bonus with all levels	Cumulative bonus
Bank I Perk 	3 PP 	1% 	30 PP 	10% 	10%
Bank II Perk 	10 PP 	1% 	100 PP 	10% 	20%
Bank III Perk 	25 PP 	1% 	250 PP 	10% 	30%
Bank IV Perk 	50 PP 	1% 	500 PP 	10% 	40%
Bank V Perk 	100 PP 	1% 	1000 PP 	10% 	50%
Bank I Quirk 	100 QP 	0.5% 	1000 QP 	5% 	55%
Bank II Quirk 	250 QP 	0.5% 	2500 QP 	5% 	60%
Bank III Quirk	500 QP 	0.5% 	5000 QP 	5% 	65%
Bank IV Quirk 	1000 QP 	0.5% 	10000 QP 	5% 	70%
Bank V Quirk 	2000 QP 	0.5% 	20000 QP 	5% 	75%
==Strategy==
Banks allow you to build up your banked resources over the course of several consecutive rebirths, meaning you can reach higher levels within the rebirth duration than would otherwise be possible. If the rebirths are of equal length, this multiplier approaches the limit:
\lim_{Rebirths \to \infty}(BankedResourceMultiplier) = 1 / (1 - BankPercent)
This applies regardless of the starting value of the banked resource, so if you bank levels from a long rebirth and then do a series of shorter runs, the level you reach each run will decay towards this limit. This presumes that you can reliably BB your resource even after it's been boosted by your bank, which can be a challenge for TM levels in particular. If you can't BB, the effective level multiplier limit is lower.
Early levels in banks will not have much impact, since the bonus limit is low and is reached (approximately) in very few rebirths. As the total bank percentage gets higher, banks become exponentially more powerful, and the extra growth of the banked resource will last for more consecutive rebirths. It's better to hold off on buying the bank perks until you can reasonably afford up to tier III-IV at least. You can buy the lower tiers for a small boost before then but there's better ways to spend your PP. 
With consistent length rebirths, a bank at maximum strength (75%, all perks and quirks unlocked) will eventually quadruple the level of the banked resource that you had at the end of rebirth zero. The effect of these extra levels is subject to any diminishing returns that normally apply to the resource being banked.
Category:Game Feature