Despite a majority of employers offering 401(k) plans where they match a portion of the amount their workers contribute, only 28% allow their employees to immediately have full ownership of that added amount. In order to reward long service employees, many employers are opting to make vesting times - "how long you must work at the company for its matching contributions to be 100% yours" - anywhere from 1 to 6 years. Experts say this should not stop employees from contributing at least enough to get the company match.
See "Workers wait years for 401(k) funds to become fully theirs", Sarah O'Brien, CNBC, June 17, 2021