(Reuters) - Agricultural Bank of China ABC.UL has received an $800 million investment from the Kuwait Investment Authority, sources said on Monday, in a deal that means Middle East funds will take up more than half of Hong Kong's cornerstone portion of AgBank's $23 billion IPO.

The sources confirmed a report issued late on Sunday that the Qatar Investment Authority had agreed to invest $2.8 billion in AgBank, a greater-than-expected amount that gets underwriters closer to its goal of raising around $6 billion through cornerstone investors.

Excluding over-allotment shares, AgBank hopes to raise around $12 billion through its Hong Kong offering, and around $11 billion through Shanghai. Non-Chinese investors are forbidden from taking part in China IPOs.

AgBank hopes to surpass Industrial and Commercial Bank of China (ICBC) (1398.HK)(601398.SS), which raised $21.9 billion in 2006, as the largest-ever IPO. China's market drop since April has forced the lender to scale back its fundraising plans from the $30 billion it hoped to haul in.

China Resources Enterprise's (0291.HK) parent company also committed to invest $200 million in AgBank's IPO, a source familiar with the matter said on Monday.

Cornerstone investors agree to buy into an IPO before it prices. They are normally locked in for six to 12 months and help establish confidence in the offering before it is marketed to institutional investors.

The investors' names should appear in the Hong Kong offer red-herring document due this week, the sources said. Other cornerstone investors include Temasek Holdings TEM.UL, Standard Chartered (STAN.L)(2888.HK), Rabobank RABO.UL and Hong Kong tycoon Li Ka Shing, whose commitments range from $100 million to $500 million each.

(Reporting by Michael Flaherty and Kennix Chim; Editing by Chris Lewis)