(Reuters) - Shares of wearable device maker Fitbit Inc (N:FIT) rose as much as 8 percent on Thursday after a previously unknown entity calling itself ABM Capital Ltd said in a regulatory filing that it had offered to buy the company for $12.50 per share.
Reuters could not immediately determine the veracity of the offer.
The filing, which contained little detail of the purported offer, listed a Shanghai address for ABM Capital and also had a typographical error in Fitbit's name.
Reuters was unable to reach ABM with the telephone number provided in the filing.
Fitbit could not be immediately reached for comment, while the U.S. Securities and Exchange Commission (SEC), which received the filing, declined to comment.
A search on the securities regulator's public Edgar database did not show any other previous filings from ABM Capital Ltd.
Concerns about the security of Edgar, where thousands of public companies and money managers make official filings, were raised last year when a firm calling itself PTG Capital Partners offered to buy cosmetics maker Avon Products Inc (N:AVP).
In another instance, a group identifying itself as shareholders of U.S. chipmaker Integrated Device Technology Inc (O:IDTI) earlier this year offered to buy the company for $32 per share.
Fitbit's shares were up 4.4 percent at $8.92 in afternoon trading, well below the purported offer price of $12.50, which represents a premium of 46.2 percent to the stock's Wednesday close.
The New York Stock Exchange had halted Fitbit's shares at 11:02 ET for volatility.
Shares of the company, which had a market value of $1.91 billion, had lost about 70 percent of their value this year through Wednesday's close.