The platform veteran, who spent 24 years at Abrdn before joining Quilter in September 2021, became unconscious on December 28, 2022, while walking with friends near the summit of Crag Hill.
His friends rang 999 and performed CPR when he collapsed, according to a Keswick Mountain Rescue Team report.
Emergency services were called at 1:39pm, but weather and visibility meant a coastguard helicopter was forced to return.
Some 19 Keswick mountain rescuers had to make their way through Force Crag mines and Coledale Hause.
A further 12 team members from Cockermouth Mountain Rescue Team were also called to assist.
“Team members arrived on scene but tragically there was nothing that could be done to save the man,” Keswick Mountain Rescue Team said in their report.
“Our deepest thoughts and sympathies go out to the man’s family and friends.”
Chief executive of Quilter, Steven Levin, said: “We are all desperately saddened by the news of David’s passing and our condolences and thoughts are with his family at this time.
“We have benefited from David’s deep industry knowledge, and I feel grateful to have worked with him. He had already made a significant impact in our business and had brought together people from across our proposition, product and marketing teams to help us create more compelling client and adviser propositions. He will be greatly missed by us all at Quilter.”
Tiller has been in the platform industry for over two decades. At Quilter, he oversaw the company's portfolio management technology, investment solutions, adviser tools, and its platform.
Before Quilter, he held the role of global head of client technology solutions at Standard Life Aberdeen, where he was responsible for the Standard Life Wrap and Elevate platforms.
He often pushed the platform industry to innovate. In a podcast last year with FTAdviser, he said platforms have done an awful lot of innovation but so far it’s all been within their own swim lanes.
“The only way we’re going to make a difference for customers is if we start innovating across the value chain and get out of siloed thinking and start thinking how it [technology] fits together,” said Tiller.
“The platforms that will be able to do it will be the ones that have actually sorted out their foundations.”
To innovate, platforms need to see themselves “not necessarily as islands”, Tiller said, and instead see themselves as part of a wider ecosystem to support advisers.