Low fees, transparency, tax efficiency and performance have made exchange traded funds the darling of financial services.

And now ETFs are set to have another thing going for them: robots.

Digital wealth management platforms - robo-advisors, as they're known - are poised to lift total assets held in ETFs by $800bn by 2020, according to a new report titled "Live digital or die" by consultancy PwC.

"We believe that… growth will dramatically accelerate as the cost benefits and ability to provide consistent advice in a retail investor friendly format drive adoption," the report said.

"If the same level of growth noted over 2015 -2016 were repeated over the next five years automated advice AUM would amount to $811bn."

Robo-advisors use ETFs to manage their clients' money.

It is a natural fit. Like ETFs, robo-advisors use technology rather than experts to make investment decisions. Robo-advisors use online questionnaires completed by clients; ETFs follow an index. Like ETFs, robo-advisors keep costs low by removing people and removing sneaky fees.

Despite the ground moving beneath their feet, the report claims, ETF providers are complacent and have feet of clay. Out of the hundreds of people surveyed across the industry, only a minority believed that robo-advisors would collect more than $50bn more in assets by 2020. Yet, on its current trajectory, that number is set to be over $800bn.

"Automated advice…endanger[s] entrenched members of the ETF industry who resist change," the report said.

"Successful ETF firms will need to embrace the fastpaced technology advances and either invest in or partner with technology firms to respond to customer demands for low-cost investment products and innovative services."

The report also warned that despite the hype around start-ups and the potential for disruption, the real winners from robo-advice would be large and powerful companies who can easily absorb the new technology.

"We believe that automated advice platforms favour large incumbent asset managers. Yes, new entrants into the automated advice market have strong visualization, apps and websites but there is little proprietary technology protecting the independent first movers that can't be bettered or replicated by incumbent organizations who also have the ability to buy this technology."