The Islamic State rakes in over $1 million per day in extortion and taxation and the dreaded terror group has enough assets to cover its expenses despite falling oil prices, according to a media report.

The group minimizes costs by looting military equipment, appropriating land and infrastructure and paying relatively low salaries, a report in the New York Times said citing analysts at the RAND Corporation, a nonprofit organization that researches public policy.

According to the analysis, the terror group collected over $1.2 billion in 2014. The breakdown states that the Islamic State raked in $600 million from extortion and taxation, $500 million from robbing state-owned Iraq banks and only $100 million from oil infrastructure.

The group also limits its vulnerability by shifting operations, transitioning between expanding its territory and fuelling terrorist activity, the report said.

The Islamic State has revenue and assets that are more than enough to cover its current expenses despite expectations that airstrikes and falling oil prices would hurt the group's finances, according to the analysts at RAND Corporation.