The BlackRock-led investors, along with Saudi state-backed Hassana Investment Co., agreed to a $15.5 billion lease-and-leaseback agreement with Aramco in late 2021, which gives the investors a 49% stake in Aramco Gas Pipelines Co.

The consortium is issuing amortising conventional bonds and sukuk to begin refinancing a $13.4 billion bridge loan that backed the stake purchase.

Reuters reported in September that BlackRock held investor meetings in London to drum up interest in the planned bond sale.

Initial price guidance was around 240 basis points (bps) over U.S. Treasuries (UST) for sukuk, or Islamic bonds, with a weighted average life (WAL) of 7-1/2 years, the document showed.

Guidance was around 275 bps over UST for a tranche with a 12-year WAL and around 305 bps over UST for Formosa bonds with an 18-year WAL. The deal is expected to price late on Thursday.

Moody's Investor Service said it expected around $11 billion to be raised from the sale of bonds and sukuk. It gave the issuers, GreenSaif Pipelines Bidco S.a.r.l. for the bonds and TMS Issuer S.a.r.l. for the sukuk, an expected rating of A1, the same expected ratings for the bonds and sukuk. Fitch Ratings assigned them expected ratings of A.

BNP Paribas, HSBC and JPMorgan are global coordinators on the debt sale. Other banks on the deal are Citi, First Abu Dhabi Bank, MUFG and SMBC Nikko.

BlackRock Inc. and its affiliates indirectly own 78.7% of the issuer through "an aggregator vehicle", a separate bank document showed. Hassana, the investment arm of Saudi Arabia's General Organization of Social Insurance, owns the remaining 21.3%.

(Reporting by Yousef Saba; editing by Jason Neely and Bernadette Baum)

By Yousef Saba