What is the difference between levered beta and unlevered beta?

beta includes both business risk and financing risk (leverage). This is what Bloomberg reports. Unlevered beta (asset beta): beta after stripping out the leverage effect → pure business risk.

If you use comps betas for a target with a different capital structure, you must delever → average the asset betas → relever to the target capital structure. Otherwise you are directly comparing companies with different debt levels. With comps of similar capital structure this is sometimes skipped, but it is best practice.