The former Barclays chief executive’s Atlas Merchant Capital and Qatari investment bank QInvest agreed to take the stockbroker private for £15.5 million ($19 million) in an all-cash deal, according to a statement on Friday.
QInvest is already Panmure’s biggest shareholder.
Diamond, 65, who stepped down from Barclays in 2012, has signalled a growing interest in pursuing bank takeovers in Europe in recent years, saying there are “terrific” opportunities as the region’s largest firms retrench.
Such purchases mark a shift for Diamond, who focused on acquiring African banks through his Atlas Mara vehicle, which is separate from the Atlas Merchant private equity firm he set up at the end of 2013.
The firms aim to “build a larger, successful boutique investment bank”, Matthew Hansen, head of UK and Europe for Atlas, said in the statement.
“This long-term stabilisation and development can only realistically be achieved as a private company, out of the glare of the public market and the effects of share price movement.”
Read also: Diamond could take Atlas Mara private
The offer is a 68 percent premium over Panmure’s closing price on Thursday. The brokerage’s independent directors unanimously endorsed the deal.
Panmure CEO Patric Johnson has sought to restore his firm to steady profits since he was put in charge in February 2016. The company drew takeover interest last year from Mehmet Dalman, the former investment banker and chairman of Welsh soccer club Cardiff City, the Sunday Times reported in August.
Panmure’s stock has climbed 3.5 percent so far in 2017, after dropping 64 percent over the past three years.
Diamond is also an investor in New York brokerage South Street Securities Holdings, which earlier this month agreed to buy Lebenthal Holdings' asset-management business and a stake in broker-dealer Lebenthal & Co.
Months after taking a stake in South Street in mid-2015, Diamond said he saw an “incredible entrepreneurial opportunity” to invest in financial companies competing with so-called systemically important banks that are facing increasing scrutiny from regulators.
In January, people with knowledge of the situation said Diamond was mulling options for Atlas Mara, including taking it public or merging it with another firm operating in Africa.