A Dutch-listed affiliate of The Carlyle Group that owns $22 billion (£10.9 billion) of mortgage-backed investments was in emergency restructuring talks with its banks last night after failing to meet repayment requests.

Carlyle Capital Corporation (CCC), an offshoot of the US private equity firm, said it had received margin calls for more than $37 million from seven of its banks since Wednesday but was unable to meet the demands of four of them. As a result, it said it had received one default notice and expected at least one more.

But there were fears last night that the fund could be unwinding after it emerged that CCC had already had to settle margin calls of $60 million in the past week prior to the latest disclosure. John Stomber, CCC's president and chief executive, said that the fund was in talks with its banks, although neither CCC nor Carlyle would comment further.

CCC, which floated in Amsterdam in July, invests in long-term asset-backed securities, such as investment grade mortgages issued by Fannie Mae and Freddie Mac, the US mortgage specialists.

Although the assets are highly rated, their value has been hit hard by reverberations from the American sub-prime credit crisis. As the values have fallen, its banks - including Bank of America, Bear Stearns, BNP Paribas, Calyon, Citigroup, Credit Suisse, Deutsche Bank and ING - have demanded more collateral as guarantees for their loans.

CCC's problems echo those of Peloton Capital, the London-based hedge fund that collapsed last week after failing to meet margin calls to repay loans used to buy mortage-backed securities.

CCC's problems are potentially a lot worse, however, given the fund's size. It raised $670 million of equity from its float and private individuals - including Carlyle partners - which it then geared up 32 times to finance a $21.7 billion portfolio of assets.

Carlyle's founders, David Rubenstein, and his colleagues Daniel D'Aniello and William Conway, were last summer twice forced to bail out the fund for a total of $200 million. It is understood that $100 million was repaid in November and CCC has borrowed another $50 million since then.

Mr Stomber said the environment over the past few days had created a situation where the margin prices of its AAA-rated securities, issued by Fannie Mae and Freddie Mac, were not representative of their underlying value.

CCC has been selling off assets since August and said yesterday it had so far sold almost $1 billion in non-mortgage backed assets.

Observers have said the bad news was obvious from the start when CCC's flotation was scaled back because of choppy credit markets.

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