Mark P. Wetjen, a member of the main U.S. derivatives regulator, is stepping down after almost four years of helping to put in place one of the most wide-ranging market oversight rewrites in generations.

Wetjen, a Democrat, pushed for increased coordination with overseas regulators as the U.S. Commodity Futures Trading Commission (CFTC) wrote rules for the swap market required by the Dodd-Frank Act following the 2008 credit crisis. Wetjen was often viewed as a more moderate voice on the commission as he looked to build consensus on cross-border oversight, rules increasing competition on new trading platforms, and limits on commodity market speculation.

"I have sought consensus globally, domestically, and within the commission itself throughout the implementation process, with the stated goals of ensuring the CFTC was properly informed as it pursued its work, and to better ensure that the reform effort would stand the test of time," Wetjen said in a resignation letter dated Aug. 14 addressed to President Barack Obama.