Four pharmaceutical companies — Johnson & Johnson, Pfizer, Merck and Abbott Laboratories — collectively kept $7 billion in tax savings in 2018 due to Republicans' 2017 corporate tax overhaul, according to a new Oxfam report.

The bottom line: Oxfam's results mirror our reporting, which shows pharmaceutical companies in particular have benefited from bringing back billions of dollars in overseas profits that have sat untaxed. However, this report says the tax savings have not led to other social goods, like more research investment in new drugs or lower drug prices.

By the numbers: The 4 companies highlighted by Oxfam mostly benefited from the repatriation of overseas cash.

$5.3 billion of the $7 billion of tax savings in 2018 came from bringing home untaxed offshore cash.

The big picture: "These are all policy choices," Niko Lusiani, a senior adviser at Oxfam, who wrote the report, said of the tax law and its effects. "And we haven't seen any big changes" in pharmaceutical industry behavior.

Oxfam focused on just 4 drug companies because they are large, representative and U.S.-based, Lusiani said.

Oxfam may take a deeper look at the pharmaceutical sector, but the group wanted to evaluate the short-term effect of the corporate tax overhaul and specifically whether drug companies were living up to their promises that the law would boost jobs, assets and productivity in the U.S.

Go deeper: Read Oxfam's report.