The SEC -- like other U.S. agencies -- uses a two-step process for writing and approving rules. The first stage is to issue a proposal and then invite public comments; the second stage is to adopt the final version. The commission votes on both stages.

So far the agency has proposed about 75 percent of its Dodd-Frank rules, and completed about 20 percent of them.

"We are currently reviewing thousands of comments from some of the proposals we issued to ensure that we get the final rules right," said John Nester, an SEC spokesman, in a statement.

Over the same timeframe, another agency working to implement Dodd-Frank, the Commodity Futures Trading Commission, has managed to accelerate its rulemaking. According to the Federal Register, the CFTC proposed or adopted about seven rules a month in the first year after Dodd-Frank and 10.2 per month since then. Though both agencies are focusing on Dodd-Frank work, including some joint rules, the rulemaking isn't always comparable.

Financial Crisis

Some of the SEC's delayed rules strike at the roots of the 2008 crisis. One example is a rule that would ban firms from designing asset-backed securities deals that put their interests in conflict with investors. The SEC didn't propose the rule until September, five months after the law said it should be adopted. The proposal's comment period was extended twice; the commission has yet to schedule a final vote.

Other rules are being drafted and revised in coordination with other regulators, complicating the process further. Those include the so-called Volcker rule to ban proprietary trading at banks, the risk-retention rule forcing lenders to keep a stake in loans they bundle and several rules defining new swaps market oversight.

Conflict Minerals

Among SEC-only measures delayed by the slowdown is a Dodd- Frank rule requiring companies to trace the origins of metals linked to violence in central Africa.

"It is critically important the SEC quickly finalize the rule," U.S. Senator Patrick Leahy of Vermont and six other Democratic lawmakers wrote to Schapiro on Feb. 16. With a rule in place, "the smuggling that has emerged will become less economically viable, and the people of central Africa will benefit from further reduced violence and increased economic opportunities."

The SEC is now almost a year past the congressional statutory deadline for a similar rule to require oil, gas and mining companies to disclose payments to foreign governments for access to resources, said Ian Gary, a senior policy manager at Oxfam America, the humanitarian group's U.S. arm.