Restricted shares exist but cannot be sold on the open market until a vesting condition or a holding period is satisfied and the legend is removed. They are counted in outstanding-shares but excluded from float, which is why float is smaller than the share count.
For traders the important moment is when restrictions lapse. A lock-up-period expiry or a large tranche of registered restricted shares adds supply on a known date, and form-144 filings flag intended sales.
Example: a company has 80M shares outstanding of which 26M are restricted insider holdings. Float is 54M. When 9M shares unlock, float jumps 17% in a day and the typical daily volume of 1.2M shares suddenly looks thin against the new supply.