US companies have abandoned $370bn of deals since Barack Obama came into power in 2009, with regulators under his administration blocking an unprecedented number of transactions to protect competition, jobs and the tax base.

Corporate America responded with dismay on Tuesday after the Treasury proposed new rules that torpedoed Pfizer’s takeover of Dublin-based Allergan, valued at $160bn, or $190bn including debt, in an attempt to stop the drugmaker moving its headquarters to Ireland so it could avoid billions of dollars in US taxes.

It was the latest in a series of interventions by branches of the Obama administration, which has thwarted more big-ticket deals than were blocked during the Bill Clinton and George W Bush eras put together, according to a Financial Times analysis of abandoned deals valued at more than $10bn.