U.S. securities regulators are extending a pilot program that aims to test whether measures designed to limit extreme market volatility are doing the trick.

The U.S. Securities and Exchange Commission (SEC) is extending its so-called “limit up limit down” pilot program for a year. It is now set to run until April 21, 2017. The SEC says it extended the test to give market participants time to conduct further analysis about how the plan is working.

In extending the plot, the SEC is also calling on the self-regulatory organizations (SROs) to come up with rule recommendations based on the results of the ongoing test, including ways to harmonize SRO rules for dealing with “clearly erroneous” executions. The regulators are also to consider other possible reforms based on the results, including ways of coordinating market reopening procedures; widening price bands during the opening period; and categorizing securities into tiers.

Separately, the SEC also announced that it will consider a possible pilot on “maker taker” fees and trading venue regulation at the meeting of its Equity Market Structure Advisory Committee on April 26.