Stockbroker Tricom Equities yesterday failed to settle all trades relating to its share trading activities from the middle of last week.The Herald Sun reported that Tricom notified the Australian Securities Exchange and other market participants that it was unable to meet the usual deadline on some share trades executed last week.The Age reported that Tricom completed settlement on a restricted list of trades after 4pm yesterday rather than at the usual time around 12.30.Tricom's failure to settle appears to be linked to the forced sale of shares under margin calls by clients during trading on Wednesday and may relate to a narrow basket of stocks (with speculation linking the margin calls and unsettled trades to stocks within the Allco and Babcock & Brown families of related companies).The firm is a niche provider of margin loans and targets high net worth, and notionally wealthy, clients.The Herald Sun reported that the firm had a margin loan portfolio of $2.2 billion at June 2007 but had reduced that subsequently.The newspaper named ANZ and Merrill Lynch as two wholesale lenders to whom Tricom owed more than $1 billion. The Australian reported that ANZ is Tricom's primary wholesale lender and suggested the bank had "not been overly supportive". The Age, ASIC filings, listed other creditors as Babcock & Brown, Commonwealth Bank and Westpac along with investment banks Morgan Stanley and Merrill Lynch.Tricom told The Australian that it was a net receiver of stock and entitled to net payments. This may mean clients are still to chip in additional cash or other collateral to cover margin calls where the sale price was insufficient to cover loans, or may mean some other stock broker has failed to make payments.The firm told the Herald Sun that "due to the exceptionally large volumes traded last week some administrative issues have arisen in settling those trades … We believe they will be resolved by the morning."