How much do the occupants of the Oval Office affect the fortunes of Wall Street? The answer depends partly on how successful they are in making their ideas a reality.

Campaign proposals often mean little if a candidate wins the general election but cannot get Congressional backing. If Republican candidate Ben Carson, a strong contender at this point for the GOP nomination, succeeds in both, U.S. and global markets could be in for a wild ride.

Carson -- who is toe-to-toe with GOP front-runner Donald Trump -- hasn't shared a formal economic plan, but he has proposed repealing the Affordable Care Act, implementing a flat tax rate and passing a Constitutional amendment requiring a balanced budget. At one point, he suggested eliminating Medicare but later changed his mind.

The retired neurosurgeon's ideas represent such substantive shifts that GOP opponent John Kasich, the governor of Ohio, called them "fantasies," a designation he also applied to Trump's economic plans.

"These plans would put us trillions and trillions in debt," Kasich said. "Why don't we just put a chicken in every pot while we're coming up with these fantasy tax games," he added, referring to a slogan from the 1928 campaign of Republican President Herbert Hoover, whose tenure included the stock market crash of 1929 and the start of the Great Depression.

Assuming that the rest of the U.S. doesn't agree with Kasich's assessment -- admittedly a big assumption -- here are four stocks that could benefit from a Carson presidency:

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1. Valero Energy

President Obama has rejected the Keystone XL pipeline, which would carry 800,000 barrels of oil from Alberta, Canada, to the Gulf of Mexico, but the project might be revived under a Carson administration, providing a significant benefit to international refiner Valero Energy (VLO - Get Report) .

"Valero wants to bring heavy Canadian crude to the Gulf Coast to offset declining supplies of heavy crude coming from Mexico and South America," said company spokesman Bill Day. "It makes more sense economically to transport the heavy crude oil to where refining capacity to process it already exists, than to build expensive new refining capacity where the heavy oil is extracted."

The San Antonio-based company, reported earnings of $2.79 per share on revenue of nearly $23 billion for the third quarter, beating estimates. While its stock is performing well, Zack's Investment Research says the company faces challenges from the cost of environmental regulation.

"The requirement of policies to reformulate fuel and lower emission from refinery operations make the industry a highly regulated one," the report cited. "As a result, companies like Valero are often forced to divert cash flows to ensure regulatory compliance, which can adversely impact profitability."

While Carson generally supports less regulation, it is unclear how he would adjust regulations for refining companies. He has, however, made it clear that he supports the pipeline.

 Keystone should have been approved several years ago," said Day, the Valero spokesman. "If the decision had been based on energy policy or economics, it would have been approved. But it has become a political issue."


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2. JPMorgan Chase

JPMorgan Chase (JPM - Get Report)  has already felt the pinch of regulations established under the Dodd-Frank financial reform law, designed to prevent another financial crisis by limiting some trading activities and requiring banks to insulate themselves with capital reserves.

CEO Jamie Dimon noted in the company's 2014 annual report that increased regulation is costing the bank both time and money.  "Part of the issue around legal costs is that banks are now frequently paying penalties to five or six different regulators (both domestic and international) on exactly the same issue," Dimon said. 

The regulatory landscape for banks might shift significantly in a Carson presidency, however. The candidate has been highly critical of the Dodd-Frank Act, and especially the Consumer Financial Protection Bureau that it created. 

In a Washington Times op-ed, Carson wrote, "The CFPB is the ultimate example of regulatory overreach, a nanny state mechanism asserting its control over everyday Americans that they did not want, did not ask for and do not need." 

It's "exactly the sort of agency I plan to rein in," he added during a televised GOP debate.

But Dick Bove, a banking analyst with Rafferty Capital Markets, said that there are hundreds of rules under Dodd-Frank that are deeply embedded into the banking system and he doesn't see repealing the law as a realistic option

"It would be virtually impossible to eliminate it, reform it, or get rid of it," Bove said. Any reform could only "chip away" at parts of the legislation, he said.

Further complicating matters is that Carson has already contradicted himself by saying that he's also tired of "too-big-to-fail" Wall Street companies, a stance that would indicate he supports more regulation rather than less. In the third quarter, JPMorgan reported profit of $1.32 a share on revenue of $23.5 billion. 



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3. UnitedHealth Group

UnitedHealth Group (UNH - Get Report)  might see a big payday if Carson convinces both houses of Congress to repeal the Affordable Care Act, which he has equated with slavery.

The law, popularly known as Obamacare, includes a 40% excise tax, known as the "Cadillac tax," on any portion of a health insurance policy that costs more than $10,200 for individuals or $27,500 for families.

While that provision doesn't take effect until 2018, Steve Wojcik, vice president of public policy at the National Business Group on Health, said the tax hurts employers who offer such plans and may prompt businesses to abandon them.

That would reduce revenue streams to insurers such as UnitedHealth, who are also hurt by the 80/20 rule that requires insurers to spend "80% of premium dollars on health-care-related expenses" and refund the remainder to customers. The requirement increases to 85% for large group markets.

UnitedHealth, which reported $41 billion in revenue in the third quarter, is estimated to have paid back $300 million under the rule, money it could save with an Obamacare repeal.

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4. Exxon Mobile

Oil giant ExxonMobil (XOM - Get Report) , which had an effective tax rate of 41% last year, including payments in the U.S. and abroad, would get to keep significantly more of the money it makes if Carson succeeded in reducing the corporate tax rate to 15% to 20% from the current 35%.

The Irving, Texas-based business paid $18 billion in taxes in 2018, topping the list of companies with the highest levies.  

"Going to a 15% or 20% corporate tax rate in the future, that will have positive economic impact," said Kyle Pomerleau, economist for the non-partisan Tax Foundation. The lower rate would prompt companies to invest more in return for a higher profit, he said.

ExxonMobil posted profit of $4.24 billion, or $1.01 per share in the third quarter, despite lower crude oil prices.

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