I-DEV International lost its CEO Jason Spindler during Tuesday's terror attack at Dusit hotel.
His brother Jonathan Spindler broke the news Wednesday in a tweet.
“Jason was a survivor of 9-11 and a fighter, I am sure he gave them hell, there are no words to describe how our family is feeling but I can say… Jason Spindler you are and will always be an amazing Son, Brother and Uncle,” Jonathan said.
Spindler's mother, Sarah, was quoted by NBC news saying her son was trying to make positive change in the third world an emerging markets.
"We all miss him so much. And it's so sad that such a bright young person is taken away by terrorism," Sarah said.
I-DEV is a strategy and investment advisory firm focused on supporting businesses and organizations to achieve their impact and growth goals in emerging markets.
The firm has presence in Africa and Latin America where it invests in growth, innovation and building leading companies in Tech, energy, agribusiness.
In Kenya, its clients are Twiga Foods - Africa’s largest web-based grocer serving at least 18,000 small and medium size vendors in Nairobi alone.
I-DEV's other clients include Conservation International, World Bank, Grupo Bimbo, Green Mountain Coffee, Burn Manufacturing (East Africa) and DFID among others.
Meanwhile, the UK Foreign office confirmed that a UK citizen also died in the horrendous attack.
"Our team at the high commissioner have been working through the night to support the kenyan authorities as they respond to this attack and to offer all the offer we can to all the British nationals who may have been caught up in it," it said in a tweet.
"I'm very sad to confirm that we believe at least one British national has been killed," the office added.
The UK government issued a travel advisory to its citizens in Kenya against making any unnecessary visits to areas perceived to the targeted by terrorists.
It said they should not come within 60km of the Kenya-Somali border, the counties of Garissa, Lamu County (excluding Lamu Island and Manda Island) and areas north of the Tana River County.
"You should continue to avoid the immediate area, remain vigilant and follow the advice and instructions of local authorities," the office said.
"There’s a heightened threat of terrorist attacks in Nairobi and the coast and resort areas of Mombasa and Malindi, and northern border counties. The Inspector General of the Kenyan police has called on the public to adopt a higher level of vigilance and report any suspicious people or activity straight away," it added.
In February last year, security agencies thwarted a terror attack targeted at key installations in Nairobi.