Fractional Kelly
Betting a fraction, typically 25-50%, of the full Kelly criterion amount to reduce variance while retaining most of the growth benefit.
Like driving at 80% of top speed -- you get there almost as fast with much less crash risk.
Why it matters
Fractional Kelly dramatically reduces drawdown risk while only slightly reducing long-term growth rate.
How DMP uses this
DMP recommends fractional Kelly for users applying systematic bet sizing to +EV plays.
Common mistake
Using full Kelly because it is optimal -- quarter Kelly captures 75% of the growth with far less volatility.