* Orders pile in for first China sovereign bond issue since 2004
* Tight pricing to help lower borrowing cost for state firms
* China sovereign CDS, SOE bonds rally (Adds graphics, CDS comparison, updates order book)
HONG KONG, Oct 26 (Reuters) - International investors are piling into a rare global bond offering from China, with orders topping $20 billion ahead of its pricing later on Thursday, more than 10 times the amount on offer.
China, which last sold a global bond in 2004, is offering 5-year bonds at 30-40 basis points (bps) over U.S. Treasuries and 10-year bonds at 40-50 bps above, in two tranches of $1 billion each.
"Everyone wants to get their hands on this bond. These are tight levels but we are interested as there is little risk of repeated issuance in the same maturity bucket," said Edmund Goh, fund manager at Aberdeen Standard Investments.
The sovereign debt sale is expected to serve as a pricing benchmark for China's state-owned firms which are among Asia's most active issuers in the offshore bond market.
"Sovereign bonds set the benchmark and create velocity for capital markets to deepen," said Henrik Raber, Standard Chartered debt capital market head. "We expect to see continued robust primary bond issuance activity across Asia, and in particular, from China."
Existing bonds from these issuers have seen spreads narrow in anticipation of tight pricing of the underlying sovereign.
Export Import Bank of China's bonds have rallied 10 bps since the sovereign debt plan was announced earlier this month.
"It will re-price the China (state-owned enterprise) curve across the board particularly higher-rated bonds like CNOOC, Sinopec, Petrochina," said Raymond Lee of Kapstream Capital adding that he would prefer investing via credit default swaps - insurance like contracts that protect against defaults.
"I would prefer to go long the CDS if I want exposure to a China sovereign, which is providing an extra around 20 bps of carry and also considered liquid. In recent times it's uncommon for the CDS to trade tighter than the bond, and it tells us that the technical bid is very strong for the new deal."
This demand for China's CDS has pushed it to levels below higher-rated sovereigns such as South Korea.
Investors say that infrequent, high profile issuers such as China can get away with pricing the bonds tightly even though the bonds are unrated.
Last month, S&P cut China's long-term sovereign credit ratings by one notch to A+ from AA-, after a downgrade from Moody's in May. The move put S&P's ratings in line with those of Fitch and Moody's.
Both S&P and Moody's cited risks from a rapid build-up in debt.
China's finance ministry has described the S&P downgrade as "a wrong decision" that ignored the economic fundamentals and development potential of the world's second-largest economy.
President Xi Jinping said at the Communist Party Congress last week that China will deepen economic and financial reforms and further open its markets to foreign investors as it looks to move from high-speed to high-quality growth.
Bank of China, Bank of Communications , Agricultural Bank of China, China Construction Bank, CICC, Citigroup, Deutsche Bank, HSBC, ICBC and Standard Chartered Bank have been hired to manage the deal.
(Reporting by Umesh Desai; Editing by Kim Coghill and Jacqueline Wong)