By Teppei Kasai
TOKYO (Reuters) - Shares in Rakuten Inc (T:4755) fell to their lowest in over two months on Monday as investors questioned the ability of Japan's biggest e-commerce firm to digest another acquisition after the company said it was considering buying a U.S. website operator.
In a statement on Saturday, Rakuten said it was in talks with U.S. rebate site operator Ebates about a potential purchase. Japanese media said any deal would be worth at least 100 billion yen (589.94 million pounds), or almost the same amount Rakuten paid for U.S. messaging app Viber in February.
San Francisco-based Ebates, which operates websites offering rebates and coupons from retailers like Amazon.com Inc (O:AMZN) and Best Buy Co Inc (N:BBY), could not be reached for comment.
"The company's basic direction on M&A is positive, but since the company has been very active in M&A, we are concerned about how soon it can make profit out of those investments," said a fund manager who owns Rakuten shares and who declined to be named because he was not authorised to speak to the media.
Shares in Rakuten, which is controlled by billionaire Hiroshi Mikitani, fell 4.2 percent on Monday, their lowest level since June 24. The benchmark Nikkei stock index closed 0.2 percent higher.
Barclays senior analyst Keiichi Yoneshima said Ebates could help Rakuten to expand its presence in the key U.S. e-commerce market, as well as enable it to offer similar products, such as coupons, at home.
Other analysts were sceptical.
"Investors will wonder whether this deal would be cost-effective when in the U.S. there's already a giant like Amazon," said Hiroyuki Fukunaga, the CEO of investment advisors Investrust.
For the past few years, Rakuten has embarked on a buying spree to reduce its reliance on Japan, which accounts for around 90 percent of revenues but where growth is constrained by a shrinking population size and weak consumer spending.
CEO Mikitani is trying to re-invent Rakuten as a one-stop-site for a global audience, along the lines of Amazon.com.
Rakuten offers online services such as financing, travel, shopping and online video. It also recently announced it would set up a Japanese low-cost carrier with Malaysian budget carrier Air Asia.
As of end-June, Rakuten had 412.4 billion yen in cash against debts 390 billion yen. It used bank loans for the Viber purchase and cash for its $315 million purchase in 2010 of Canadian e-book reader Kobo.
(Additional reporting by Ayai Tomisawa and Hideyuki Sano; Editing by William Mallard and Miral Fahmy)