Thomas M. Sullivan has been busy these days. The attorney at Nelson Mullins Riley & Scarborough in the District fields dozens of calls from local business owners trying to wrap their heads around financial reform.

“Small businesses are anxious. They’re uncertain what’s going to happen when there’s a new cop on the beat,” he said, referring to the newly created Consumer Financial Protection Bureau.

Though Sullivan can offer a myriad of probable impacts, there is little certainty in any scenario as proposed measures may morph along the road to implementation. Still, small businesses are bracing themselves for changes in government policy that some observers say could prove detrimental.

Take corporate tax reform. The Obama administration wants to eliminate many abatements and credits to offset a reduction of the 35 percent tax on corporate profits. A recent study released by Ernst & Young, however, concludes that such a move could raise the tax burden on small businesses by about 8 percent, or $27 billion, per year.

Many mom-and-pop shops enjoy those tax breaks that stand to disappear, but would not benefit from the lower corporate rate because they pay taxes through their owners’ individual returns.

“If they want to make more businesses competitive, then they should move more businesses toward the pass-through structure and not away from it,” said Brian Reardon, executive director of the S Corporation Association, which commissioned the Ernst & Young study.

Treasury Secretary Timothy F. Geithner has been sounding the horn on tax reform for months, with some media organizations reporting a tax package to come as early as this month. The Treasury Department is reportedly considering making businesses with more than $50 million in gross receipts pay corporate income tax.

Until the agency issues a proposal, tax reform and its impacts remain up in the air. A more pressing concern is the summer rollout of the Dodd-Frank Act. Banks anticipate hiring more compliance officers to manage the law’s reporting requirements, an expense small businesses worry will translate into higher lending costs, Sullivan said.

“If the cost of credit goes up, you’ll potentially have a shock wave go through the small-business community at a time when we need people putting money on the street,” he said.

For now, the Federal Reserve says banks have been loosening lending standards to spur loan growth. What’s more, Dodd-Frank includes an amendment requiring the new consumer bureau to study small-business implications when issuing rules. Elizabeth Warren, the front-runner to head the agency, has thrown support behind the amendment, but Sullivan stressed nothing is guaranteed.

The threat of higher costs of capital is compounded by concerns about the end of the Federal Reserve’s asset-purchase program, or quantitative easing, in June. Higher Treasury yields, observers say, will increase rates, making it more expensive for small-business owners to get lines of credit.

Recent reports from Merrill Lynch forecast “a gradual, slow rise in interest rates,” noted Heather Evans, a Vienna-based vice president and wealth management adviser at the company. She advises clients to consider locking in rates on their outstanding debt.