Quindell's stock has fallen about 70 percent in the past four months after U.S.-based Gotham City Research raised questions about its revenue model and profit quality.

"Even though we may not look to list in the UK in the near future, that doesn't mean we wont look at the U.S. We are looking at all options," Chairman Robert Terry told Reuters.

The company said in June that its application for a premium listing on the London Stock Exchange had been turned down.

Quindell, which has a market value of about 920 million pounds, said it did not meet a rule that its business should not have undergone significant change in scale or operations over the previous three years.

Quindell's volatile stock, which is listed on London's Alternate Investment Market (AIM), was down 8.8 percent at 191.9 pence at 1013 GMT after the company reported first-half results.

The stock had gained more than 25 percent over the previous two days.

Quindell has started legal proceedings against Gotham City Research and a blogger who it says made defamatory statements about the company.

Terry said that Quindell was seeking unspecified monetary compensation from the short-seller.

"(We are seeking) compensation for the damage they tried to do to the business and of course they have done to the share price in the short term," he said.

The company, whose customers include British American Tobacco Plc and ING Groep NV, reported a near-quadrupling in first-half pretax profit to 153.7 million pounds. Group revenue more than doubled to 357.3 million pounds.

(Editing by Gopakumar Warrier and Ted Kerr)

By Noor Zainab Hussain