* Co says to look at better risk management of assets

* Its investments took hit after markets crashed in March

* Group revenue fell 9%, assets value fell by a quarter

JOHANNESBURG, Oct 26 (Reuters) - South Africa's state-owned Industrial Development Corporation (IDC) said it would diversify its equity investments after reporting on Monday a sharp decline in the value of its top three holdings in listed companies.

The IDC is South Africa's biggest financing institution and provides loans to projects that help develop the country's industrial capacity. It also invests in shares of companies listed on the Johannesburg Stock Exchange (JSE).

For the financial year that ended in March 2020, IDC said its stakes in Sasol, Kumba Iron Ore and BHP saw losses amounting to a combined 30 billion rand ($1.85 billion).

" are already looking at better diversification of this portfolio plus a much more active asset management approach towards these assets," said IDC Chief Executive Tshokolo Nchocho.

The company said its shares in petrochemical firm Sasol, in which it owns an 8.5% stake, were hit by a drop in the oil price and challenges at the Lake Charles project in the United States. The stake was worth just 2 billion rand at the end of the 2020 financial year, down from 24 billion rand a year earlier, it said.

Global stock markets, including the JSE, plunged in March as countries went into lockdown to curb the spread of the coronavirus although the JSE's main index has rebounded since then.

The IDC's results were also hit by a depressed South African economy due to the impact of the COVID-19 pandemic and significant losses at subsidiaries, which led to a rise in non-performing loans.

Group revenue fell 9% to 16.3 billion rand while its asset value fell 24% to 109.6 billion rand in the 2020 financial year.

As part of its risk management approach, it said it would invest in smaller portions of projects, co-fund some investments and narrow the regions in which it invests across the continent whilst supporting economic recovery. ($1 = 16.1822 rand) (Reporting by Tanisha Heiberg Editing by Promit Mukherjee and Susan Fenton)