Contributions for employees must be made within 30 days after a pay-period, while employers may match any time before their tax filing deadline.

Salary reduction contributions to a SIMPLE IRA must be made no later than 30 days after receiving the paycheck in the calendar year that reflects their deferral. Employer contributions can be made each pay period, but they must be made by the same due date as their tax-filing deadline. This can be the extended deadline.

Even if an employer files before the deadline, contributions can be made until the actual deadline date. This means that an employer can finish paying their 2015 match by October 15, 2016.