The interest income received from older Industrial revenue bonds may be taxable to the holder at regular income tax rates if the holder is:

the "substantial user" of the facility built with the proceeds of the issue.

Explanation:

An Industrial revenue bond (IRB) can be defined as any municipal debt security issued by a local or state government agency with respect to a private firm which intend to undergo a particular project such as building facilities,  purchasing heavy machinery or equipments.

The interest income received from older Industrial revenue bonds (IRB) may be taxable to the holder at regular income tax rates if the holder is the "substantial user" of the facility built with the proceeds of the issue because in the true sense it is only beneficial to the holder and not the larger community.

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