One Wall Street brokerage now favors online streaming giant Netflix over e-commerce behemoth Amazon because of Sen. Elizabeth Warren's proposal to break up Big Tech, which may gain traction on a progressive platform.

BMO Capital Markets told clients on Friday that it's made Netflix its top technology stock in light of the Massachusetts Democrat's plan to bust up Amazon, Facebook and Google.

"We continue to seek out how the legal path might progress for these types of actions, but in the short term, we think it's appropriate to move Netflix to Top Pick and Amazon to No. 2," analyst Daniel Salmon wrote in a note to clients.

"We have less confidence in the subject being a wall of worry to climb and instead increasingly clouding the fundamental thesis for Amazon," he added. "Netflix, on the other hand, faces little to no regulatory risk, in our view; thus, we are more comfortable with it in the Top Pick slot at the moment."

Warren, who announced her bid for president last month, published in a lengthy blog post on March 8 that her administration would make "big, structural changes to the tech sector to promote more competition—including breaking up Amazon, Facebook, and Google."

The longtime progressive praised prior antitrust litigation — including the government's case against Microsoft in the 1990s and the dissection of Standard Oil a century ago — for its ability to promote a more competitive marketplace.

"The government's antitrust case against Microsoft helped clear a path for Internet companies like Google and Facebook to emerge," Warren wrote. "The story demonstrates why promoting competition is so important: it allows new, groundbreaking companies to grow and thrive — which pushes everyone in the marketplace to offer better products and services."

Even if Warren is not elected, this progressive backlash could prove another political headache for Amazon CEO Jeff Bezos, whose business and logistical prowess has helped grow the online retailer into the third-largest public company in the United States with a value of $828 billion.

Amazon announced last month that it will not build a headquarters in New York City following local opposition, the company said in a statement. Local and state leaders had voiced popular opposition to the company's plan after New York City and state had offered the company performance-based incentives amounting to nearly $3 billion.

Shares of both companies rose in premarket trading Friday, with Netflix up 0.5 percent and Amazon up 1.2 percent. Separately, KeyBanc upgraded Amazon to an overweight rating.