Harbinger Capital, the American hedge fund investor, suspended takeover talks with Inmarsat yesterday, sending the satellite operator's shares sliding amid fears that a bid worth at least £2.4 billion might never emerge.

Despite Harbinger's insistence that it remained interested in taking control of Inmarsat, the satellite company's shares fell as much as 12 per cent amid concerns that regulators might take 18 months to clear a bid. The shares closed down 46p, or almost 9 per cent, at 446p, valuing the group at just over £2.1 billion.

Inmarsat said that preliminary talks had been dominated by the regulatory process relating to a potential offer. If Harbinger wanted to make a formal bid for Inmarsat, it would have to gain approval from the Federal Communications Commission (FCC), the American regulator that oversees the sector. This could take up to a year and a half to complete, particularly as a new administration may move FCC officials after this year's US elections.

Inmarsat said: “[Harbinger] has neither made an offer for the company nor indicated a potential offer price and the board of Inmarsat has therefore concluded that there is no merit in continuing discussions at this time.”

Harbinger said that the suspension of talks was mutually agreed and that it would have been inappropriate to indicate a formal price for a bid because of the regulatory delay. It said: “Harbinger remains interested in acquiring control of Inmarsat and is therefore actively considering whether to pursue the relevant regulatory and competition approvals.”

The hedge fund said that once the approvals had been obtained, it would be keen to talk to Inmarsat to see whether a deal could be agreed.

Harbinger, run by Philip Falcone, a former Barclays Capital trader who has built it into a $26.5 billion (£13.2 billion) fund, has 28.2 per cent of Inmarsat. As well as being bullish on the satellite industry, Harbinger is attracted by the role Inmarsat might play in a satellite-based US mobile phone network.

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