Agency pays few rewards, although it receives many tips of tax underpayments.

Agency pays few rewards, although it receives many tips of tax underpayments.

Buffett-ducking billionaires avoid reporting cash gains to IRS.

Buffett-ducking billionaires avoid reporting cash gains to IRS.

Agency looks at how company avoided taxes by shifting profits to offshore subsidiaries.

Agency looks at how company avoided taxes by shifting profits to offshore subsidiaries.

More than 160 lobbyists encourage Congress to pass repatriation break.