Velocity of ringularity How fast is a ringularity1 spinning? Spinning black holes are created from spinning stars.
The angular momentum of the 'parent' star must be conserved so spinning black holes are spinning much much faster than their 'parent' star.
Since black holes have generally less mass than their parent star and mass is found only in a tiny amount of space then the ringularity should be spinning incredibly fast.
The ringularity is a ring which contains all the mass of the black hole and it is in the center and it is almost infinitely tiny so it must be spinning almost infinitely fast.
Can it spin faster than c? Is there any way to know if SR can be violated inside such extremely dense objects?
1Ring singularity
$$
    K_\text{min}=2\pi\sqrt{a^2+3(ma^2)^{2/3}}
\tag{1}
$$
where the quantities $m$ and $a$, both of which have units of length, are defined by
$$
    m=\frac{GM}{c^2}
\hskip2cm
    a=\frac{J}{Mc}.
\tag{2}
$$
The maximum spin is a=m (an extremal Kerr black hole), the borderline case between a black hole and a naked singularity.
More details from Chiral Anomaly here:
https://physics.stackexchange.com/a/469282/