UPDATE 1-ChemChina raises $20 bln for Syngenta deal via perp bonds, preferred shares


* Bank of China invests $10 bln via perpetual bond

* Investment makes state-owned lender largest financier to deal

* New financing reduces ChemChina's short-term debt burden (Adds details of financing, background)

HONG KONG, May 25 (Reuters) - ChemChina has raised $20 billion in perpetual bonds and preferred shares to finance its acquisition of Swiss seeds maker Syngenta, according to a regulatory filing by the state-owned Chinese company.

ChemChina has restructured the financing of its Syngenta deal to take on more equity and reduce its short-term debt burden, but will still have nearly $20 billion in loans to refinance within 18 months, the filing shows.

Bank of China (BoC) has invested $10 billion via a perpetual bond, making the Chinese lender the single largest financier in the $44 billion deal, according to the May 18 filing which also shows state-owned asset manager China Reform Holdings Corp Ltd has provided $7 billion via a perpetual bond.

China's Industrial Bank Co Ltd has invested $1 billion through the same means, while Morgan Stanley has provided $2 billion via convertible preferred shares.

The ambitious takeover is nearing the finish line after regulators last month granted the final approvals and as more than 80 percent of Syngenta shareholders voted in favor. .

The deal gives China a portfolio of top-tier chemicals and patent-protected seeds to improve agricultural output, but has also left ChemChina facing a hefty debt burden which it has been seeking to reduce by bringing in more equity investors and replacing short-term loans with longer-term debt.

ChemChina last year arranged $32.9 billion in bridge loans from more than 20 Chinese, European and Asian lenders, stoking concern among investors and analysts over its leverage. The company has been trying to increase the ratio of equity financing and last year raised $5 billion from a Chinese fund.

Perpetual bonds are financing instruments that can act as both equity and debt. They are typically treated as equity under accounting standards but rating agencies may still treat them as debt depending on the circumstances. Because perpetual bonds have no maturity date, the new financing should help improve ChemChina's overall debt position.

China National Chemicals Corp, as ChemChina is officially known, did not respond to requests for comment. A spokeswoman for Bank of China declined to comment. A spokesman for Syngenta said post-close financing will be finalized in the second half of 2017.

China Reform Holdings spokeswoman did not immediately respond to a Reuters request seeking comment. Industrial Bank and Morgan Stanley could not immediately be reached for comment.

In addition to the new financing, which has been privately negotiated, ChemChina on Wednesday publicly marketed another smaller-sized U.S. dollar senior perpetual bond, Thomson Reuters IFR reported. The offering was hugely oversubscribed, despite rating agency Moody's downgrading of China's sovereign debt on the same day. (Reporting by Carol Zhong of Basis Point, Julie Zhu and Alasdair Reilly; Additional reporting by Aizhu Chen, Prakash Chakravarti and Tessa Walsh; Writing and additional reporting by Michelle Price; Editing by Muralikumar Anantharaman)