The shares of major banks fell Thursday and Friday after feeling the residual effects of the London interbank offered rate scandal.

Mike Mayo, an analyst with CLSA ltd, is quoted in a FiveStarEquities report as saying the probe into the banks rigging of Libor is already hurting Barclays and could eventually trip up major U.S.-based banks, including Citigroup (C), JPMorgan (JPM) and Bank of America (BAC).

Barclays was forced to pay a $451.4 million fine for attempting to rig benchmark interest rates. FiveStarEquities says the problem extends across the Atlantic with regulators currently investigating Bank of America, Citigroup and JPMorgan.

The research firm warned that any bank linked to the issue faces the potential of civil suits.

Bank of America's stock was down 1.79% by mid-day Friday. Meanwhile, Citigroup's shares (C) declined 1.96%, and Wells Fargo's stock (WFC) was down a little under 1% mid-day Friday.

JPMorgan Chase's stock (JPM) also fell approximately 1.21% in the first half of Friday trading.

The same day the Nasdaq Bank Index was down 8.92%, suggesting an overall weak performance for bank stocks this week.