A handful of moderate Senate Democrats will probably determine whether Congress can pass legislation making the most significant changes to the Dodd-Frank financial overhaul since it was enacted five years ago, in the wake of the economic crisis.

Four moderates were among the 10 Democrats on the Senate Banking Committee who opposed a 200-plus-page banking regulatory relief package that moved through the panel last month. The bill would ease federal oversight of regional banks, change some Federal Reserve operations and lessen stringent mortgage writing standards.

The chairman of the Senate Banking Committee, Alabama Republican Richard C. Shelby, remained optimistic after the markup. “There’s a lot of commonality there and common interest,” he said. “It’s not perfect, but it’s a good start.”

As negotiations over the legislation move behind closed doors, Democratic moderates are likely to be targeted by the GOP and their allies in the financial services industry.

The support of the moderates would put more pressure on the committee’s more liberal ranking Democrat, Sherrod Brown of Ohio, to reach a broader bipartisan deal with Shelby. And even if a big accord is elusive, the support of at least a few of the committee Democrats would improve the bill’s prospects for Senate consideration.

Republicans had written the measure with hopes of peeling off those moderates to build support for moving it to the Senate floor, where it would need 60 votes to advance.

The GOP-controlled House is likely to back whatever can move in the Senate, while the White House, which already said it would veto the Shelby bill, would only back the narrowest changes.

The moderates — Mark Warner of Virginia, Jon Tester of Montana, Heidi Heitkamp of North Dakota and Joe Donnelly of Indiana — have criticized the GOP for not including them in drafting the bill before the markup, but have largely avoided attacking the legislation’s policy provisions.

Warner said at the markup there are areas for finding common ground in the bill with bipartisan talks. “Dodd-Frank is not perfect, there needs to be perfections,” he said.

Attractions for Moderates

Among the provisions that might appeal to Warner are those based on bills he’s backed that would prohibit the Treasury Department from selling shares of Fannie Mae and Freddie Mac without congressional approval and another requiring more transparency from the National Credit Union Administration, lobbyists and analysts said.

Republican aides to the Senate Banking Committee said the provisions in the section of the bill related to capital markets, including allowing federal and foreign regulators to share swaps data, have not been opposed by Democratic staff members of the Banking Subcommittee on Securities, Insurance and Investments, where Warner is the ranking member.

Tester, who is the chairman of the Democratic Senatorial Campaign Committee, is seen as open to argument on changes to Dodd-Frank from the financial services industry, a powerful fundraising force.

Tester has not ruled out supporting an increase in the asset threshold for a bank to be designated a systemically important financial institution (SIFI), which brings increased federal oversight and more stringent capital and liquidity standards.

Many Democrats view that as a central feature of Dodd-Frank, and it has been one of the most contested and heavily lobbied provisions in the bill. The current bill would raise the SIFI threshold from $50 billion or more in assets to $500 billion.

Banking groups back the higher threshold because they say the lower level in the current law unfairly targets regional banks that do not pose a systemic risk to the nation’s financial system.

Lobbyists and analysts said the bill already contains a provision, drawn from a Heitkamp bill, that would end a requirement for banks to send out annual notices to account holders. One analyst noted Heitkamp could also face pressure from U.S. Bancorp, one of her state’s largest employers with about $400 billion in assets, to back an increase in the SIFI threshold.

Donnelly meanwhile, has expressed support for easing the mortgage rules, a feature of the Shelby bill. It also contains legislation Donnelly has backed that would raise from $10 billion to $50 billion the threshold for banks that fall within the Consumer Financial Protection Bureau’s supervision.

Warner and Heitkamp were not in Congress when the Dodd-Frank law was enacted. Donnelly and Tester supported it.

Sen. David Vitter, R-La., offered and withdrew several amendments at the markup, including two that might be supported by Democrats in negotiations.

One proposal would have set minimum equity requirements for banks with more than $500 billion in assets at 10 percent. It is based on legislation Vitter and Brown sponsored in the last Congress.

Democrats and Shelby also indicated interest in another amendment filed by Vitter that would end an exemption that allows only two banks, Goldman Sachs and Morgan Stanley, to own physical commodities. The amendment wasn’t considered.

Banking Committee member Bob Corker, R-Tenn., predicted there could be common ground in coming weeks on changes to the Federal Reserve, oversight of government-sponsored enterprises and provisions making it easier for smaller businesses to raise venture capital.

“My sense is there is an opportunity here before we go to the floor to do [something] a lot broader than what is here being offered by” Democrats, Corker said.