What are the notice requirements to employees when a matching contribution is suspended in mid-year?

[katieinny]

An employer has decided that it can no longer afford to make matching contributions to the 401(k) plan. The last matching contribution was made for the pay period that just ended. However, employees won't be notified for several more days. It seems to me that employees should be notified prior to the the last match so that they can stop deferring if they choose to do so. What are the employer's obligations relating to the match?