Lawsuits are piling up for the banks being investigated for manipulating Libor, according to the Wall Street Journal. Financial institutions such as Barclays, Bank of America, Citigroup and J.P. Morgan Chase could be facing dozens of lawsuits from individual investors, institutions, insurers and lenders.

Estimates of the extent of damages vary as it will prove difficult for plaintiffs to prove in court that banks caused them to suffer a loss because of manipulated rates. Analysts say banks will be under pressure to settle some of the suits.

Bondholders receiving interest set at a spread above Libor probably have the strongest suit, one finance professor says, as they can show they were paid too little interest. Money managers such as BlackRock and Vanguard have not yet taken legal action, but are looking into whether their funds could have been harmed by rate-rigging. It is unlikely that banks will sue other banks, however.