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May 7 (Reuters) - Saudi Arabia's Public Investment Fund plans to issue benchmark-sized bonds in three tranches, fixed-income news service IFR said on Thursday, as the sovereign wealth fund returns to debt markets to help finance the kingdom's economic diversification.

Initial price guidance was set at around 130 basis points over U.S. Treasuries for a three-year bond, 135 bps over for a seven-year tranche and 170 bps over for 30-year paper, IFR said. The bonds are expected to price later on Thursday.

Citi, Goldman Sachs International, HSBC and J.P. Morgan are acting as joint global coordinators.

The PIF last tapped debt markets in January, raising $2 billion from 10-year Islamic bond sale.

The fund, which manages close to $1 trillion in assets, is central to Saudi Arabia's Vision 2030 programme to diversify the economy away from oil, requiring hundreds of billions of dollars in investment.

The planned sale comes as Saudi Arabia and related entities continue to raise debt amid heavy spending demands and regional upheavals.

Saudi Arabia reported a first-quarter budget deficit of 125.7 billion riyals ($33.5 billion), as it hikes spending to support the economy amid disruption caused by the Iran war.

The kingdom's National Debt Management Center said this week it had completed its 2026 annual borrowing plan, having secured around 90% of funding needs before recent regional geopolitical events.

The plan envisaged financing needs of about 217 billion riyals ($57.86 billion), including the projected deficit and debt repayments.