Prime Minister Mark Carney is expanding the scope of a major investment tax write-off, adding oil and gas pipelines, mining property and more to the list of assets eligible for accelerated deductions in Canada. Carney will announce the tax measure Tuesday as his government hosts an investment summit in Toronto. Dozens of firms have gathered at Toronto's Four Seasons hotel to discuss possible stakes in Canadian projects in natural resources, manufacturing and other sectors.

The expansion means it will now apply to businesses that spend on aircraft, fiber-optic cables, Canadian-made passenger vehicles and more. Reform is needed because "we have had a productivity issue in this country," Carney said in an interview with Bloomberg News. The change covers roughly two-thirds of the categories of assets that companies invest in, up from 15% currently.

The document states that extending and expanding tax relief will reduce Canada's marginal effective tax rate on new business investment to 6.4% from 13% — the lowest among Group of Seven countries, and half the rate in the US. The change takes effect right away and is permanent.