The Share Centre has agreed to buy 15,000 customer accounts from Beaufort Securities.
The company reached an agreement with PwC, Beaufort Securities's administrator, after a competitive tender process.
The deal is one of three which The Share Centre has completed recently - though it has said it cannot reveal the details of the other two since the clients have not been informed yet.
In total the three acquisitions bring around 38,000 customer accounts to The Share Centre.
In its results for the six months to the end of June, The Share Centre said: "These three acquisitions represent a significant increase in overall customer numbers, and we look forward to welcoming them all to The Share Centre as the acquisitions complete.
"We very much look forward to welcoming all our new customers, especially those from Beaufort Securities who we expect to join The Share Centre from September."
Beaufort Asset Clearing Services Limited was placed in administration by UK regulators in March 2018 shortly after the US Department of Justice brought criminal charges against Beaufort Securities Limited (BSL) for its alleged involvement in securities fraud and money laundering.
Beaufort Asset Clearing Services Limited provided the clearing and custody services to Beaufort Securities Limited.
There were approximately 17,000 retail clients and approximately 500 corporate clients in Beaufort Asset Clearing Services Limited.
Beaufort Securities was declared in default by the Financial Services Compensation Scheme in April, which announced last month it would be paying out to the company's clients, the "vast majority" of whom will get all their money back.
In its half-year results, The Share Centre saw its assets under administration increase by 18 per cent to £5bn while it fell into the red, making a statutory loss of £279,000 compared to a profit of £13,000 for the same period last year.
Richard Stone, chief executive of The Share Centre, said: "These results show the positive progress the business continues to make.
"Strong revenue growth and assets now totalling £5bn for the first time are evidence of our progress and we are delighted that our service levels continue to be recognised by high profile industry awards.
"Today's announcement of three acquisitions covering around 38,000 customer accounts is particularly encouraging, and we are especially pleased to welcome, in a few weeks' time, customers of Beaufort Securities, who have endured a very difficult period since the collapse of that business in March."
8 August 2018: This article has been updated to make clear the US Department of Justice brought criminal charges against Beaufort Securities Limited (BSL).
damian.fantato@ft.com
