Apple will be a big beneficiary of President Donald Trump's tax reform plan, according to a top Wall Street firm.

The Trump and Republican Congress tax reform plan calls for a corporate tax rate reduction to 20 percent from 35 percent and a lower repatriation tax rate for U.S. companies' accumulated foreign earnings.

Bank of America Merrill Lynch reiterated its buy rating on Apple shares, saying the company's earnings would surge under the plan.

"We look at two aspects of potential tax law reform and their implications on Apple. … We conclude that: existing deferred tax liability on the balance sheet could allow for substantially all of Apple's foreign cash to be repatriated to the U.S.," analyst Wamsi Mohan wrote in a note to clients Monday.

"Importantly given the access to the [repatriated] cash, investors will likely assign a higher multiple to shares of Apple."

Apple shares are up 0.4 percent during Monday's premarket session.

Mohan reaffirmed his $180 price target for Apple shares, representing 16 percent upside to Friday's close.

The analyst said if Congress lowers the corporate tax rate to 20 percent from 35 percent and interest expense becomes nontax deductible, Apple earnings per share will benefit by 77 cents in fiscal 2018 and by 89 cents in fiscal 2019.

In addition, Mohan said the company has $223 billion of "unrestricted" cash held overseas that could be brought back to the U.S. under the plan's lower repatriation tax rate. He assumes a repatriation tax rate of 8.75 percent versus the current 35 percent rate for his analysis.

Mohan also shares what he believes Apple could do with the newly repatriated cash:

1) "Increase the rate of buybacks and dividend increases: More domestic cash could help Apple buy back more stock or further raise its dividend." 2) "Invest more in R&D: Apple could use the repatriated cash to invest more in R&D within the U.S." He also said Capex plans could change based on any new expensing rules. 3) "Invest more in M&A: Apple could use the cash to fund more acquisitions of companies within the U.S." 4) "Pay down debt: If interest expense is no longer tax deductible in the U.S., it may be in Apple's interest to pay down any U.S. domestic debt sooner."

Despite some recent volatility, Apple' stock is significantly outperforming the market. Its shares are up 34 percent year to date through Friday compared with the S&P 500's 14 return.