Vanguard released its small-business-focused How America Saves report on Thursday, which found small 401(k) plans are mirroring trends seen at larger companies.
Half of all private-sector employees work at a small business, according to the Small Business Administration.
One-quarter of small 401(k) plans administered by Vanguard's small-business 401(k) service, Vanguard Retirement Plan Access (VRPA), allow employees to begin contributing to the plan immediately after hire, and 60% require tenure of less than a year.
VRPA serves more than 2,700 plans and 125,000 participants at small businesses.
More than half of workers are saving at least 5% of their income, and nearly one in five are saving 10% or more.
Almost three-quarters of employers are making contributions, too, the survey found.
"We started offering DC plan services to small businesses, recognizing that this segment of the market was underserved and overcharged," Crystal Hardie Langston, Vanguard principal and head of VRPA, said in a statement. "We are pleased with the adoption of the service and the commitment by small business owners to offer robust, thoughtfully constructed plans to their employees."