* Muddy Waters questions value of company's forest assets
* Superb Summit is latest Chinese firm targeted by short-sellers
* Shares in Superb Summit fall 6 pct before trading halt (Adds manager of independent valuation firm, short-selling data)
By Nishant Kumar and Anne Marie Roantree
LONDON/HONG KONG, Nov 20 (Reuters) - Investment research firm Muddy Waters, whose negative reports have decimated shares of Chinese companies listed overseas, has questioned the balance sheet of timber firm Superb Summit International Group , hitting its stock on Thursday.
The allegations, which coincide with the launch this week of a tie-up between the Hong Kong and Shanghai stock exchanges that gives global investors greater access to Chinese stocks, come after a string of corporate scandals that underscore the perils of doing business in the world's second biggest economy.
A report from Muddy Waters founder Carson Block, a short-seller who has exposed accounting problems at a slew of Chinese firms, questioned the value of the assets owned by Superb Summit.
Block questioned in particular forestry assets in China that the timber company valued at HK$3.35 billion ($432 million) in its first-half results.
Superb Summit, which is worth $1.6 billion on the Hong Kong stock exchange, declined to comment.
Block told Reuters that Muddy Waters had conducted checks and was convinced the loss-making company had little or no forest ownership. In addition, the value of the forest assets and other assets belonging to the company could be much lower than it had stated, Block said.
"We have tried to find ownership of these forestry assets and have been unable to do so," Block said.
Assuming Superb Summit actually owned the forest assets, they would be worth less than HK$200 million, Block said.
"To us, Superb Summit is an empty box."
Muddy Waters' report also challenged the value of Superb Summit's May 2014 acquisition of stake in a coal liquefaction company, Beijing Jin Fe Te, saying "paying HK$1.5 billion for JFT would be like paying for a Bentley and getting a bus pass".
Superb Summit's 2014 interim report said the HK$1.5 billion valuation of intangible assets, referred to by Muddy Waters, had been measured by an independent valuer, Beijing Tian Hai Hua Valuation Firm.
Reached telephone, Tian Hai Hua's general manager, Hong Xiyi, told Reuters he stood by the valuation, which he said was based on a reasonable assessment of technologies developed by JFT.
Superb Summit declined to comment on Muddy Waters' allegations when contacted by Reuters twice by telephone and once by email.
The company has been in the red since 2011 but its shares have risen 370 percent over the past year.
On Thursday, its shares dropped as much as 6.4 percent before trading was halted at the company's request, lagging a flat benchmark Hang Seng Index.
The Hong Kong stock exchange declined to comment, citing its policy of not commenting on individual stocks.
Short sellers borrow shares and then sell them, betting the price will fall and leave them with a profit when the stock is bought back more cheaply and returned to its owner.
"Shorts" started to attack Superb Summit aggressively in late September, according to data from Markit. Nine of every 10 shares of the company that can be borrowed are currently on loan, up from just one in 10 as of Sept. 22, the data showed.
Superb Summit is ranked No. 4 in the list of the most preferred short positions in Hong Kong, as measured by the percentage of stocks on loan, Markit data shows.
Asset managers Vanguard Group and BlackRock are among the international shareholders of Superb Summit, according to Reuters data. BlackRock declined to comment. Vanguard did not immediately respond to a request for comment.
Allegations of accounting malpractice against Chinese companies have surfaced regularly in recent years, denting the reputation of the emerging giant's capital markets.
Earlier this year stock researcher Anonymous Analytics accused Chinese chemical company Tianhe Chemicals of doctoring its books ahead of a Hong Kong IPO, an allegation that has been firmly rejected by the firm.
In a separate scandal, German-listed Chinese shoe maker Ultrasonic AG came to the brink of insolvency after a top executive briefly disappeared, along with the shoemaker's cash.
Block is perhaps the best known member of a group of short-selling investors and financial bloggers who exposed fraudulent accounting practices among China-based companies with U.S. or Canadian stock listings.
Chinese forestry company Sino-Forest, targeted by Block in 2011, was the most prominent among a series of accounting scandals that have tainted the image of Chinese companies. The scandals have prompted trading halts, de-listings, lawsuits and regulatory probes in financial centres around the world. (1 US dollar = 7.7553 Hong Kong dollar) (Additional reporting by Simon Jessop in LONDON; Umesh Desai, Elzio Barreto, Michelle Price, Twinnie Siu, Lawrence White and Lisa Jucca in HONG KONG; Editing by Lisa Jucca and Alex Richardson)