Hargreaves Lansdown co-founder Peter Hargreaves has blasted advisers' "tame excuses" for not having more of their clients' wealth invested in US equities.
Mr Hargreaves, who has somewhat more than £2bn invested in equities either directly or via funds, said the US was "the world's largest and most entrepreneurial market".
He said: "For 40 years I have been surprised at UK wealth managers' omission of exposure to this incredibly important country.
"Most portfolios have less than 10 per cent in the US - some have none. The excuses have been endless but most quoted has been 'lack of decent US invested funds.' A lame excuse - even a tracker would have been better than shunning the market."
A year ago Mr Hargreaves provided the seed capital for the creation of Blue Whale Capital, an asset management business, and the Blue Whale Growth fund, the company's first fund, which has about 60 per cent of its capital invested in US equities right now.
Mr Hargreaves said his initial investment of £25m in the fund has increased in value by more than £6m in the year as a result of investment performance.
He said the desire of the manager of the fund, Stephen Yiu, to have significant exposure to the US market was a major reason for the decision to back the fund.
The Blue Whale fund has returned 24 per cent in the year since its launch, compared with 9 per cent for the average fund in the IA Global sector in the same time period.
Mr Hargreaves said: "I don't think I have ever made an investment that has returned this much for me in its first year – it has been the best performing fund in my portfolio.
"And even more pleasingly, I see of no reason why this level of performance shouldn't carry on far into the future and I will continue to add to my holding."
Mr Hargreaves also has a long standing investment in the £5.2bn Lindsell Train Global Equity fund, which has US equities as the largest geographical exposure.
Describing his reasons for investing in the Blue Whale fund, Mr Hargreaves said: "I have been, for some time, keen to seek and invest with a young investment team that I could trust.
"Most well-known managers today are approaching, or are over, 60-years-old. Managing money diligently is hard work and time consuming - very few sexagenarians have the energy or motivation. What happens when they retire?
"I don't want to sell their funds because I would pay an enormous amount of capital gains tax. The question is 'will the new manager fill the retired guru's boots?' Unfortunately there are endless examples where the new man was not up to the job."
Mr Yiu formerly worked as a fund manager at Artemis and New Star, and is a former employee of Hargreaves Lansdown.
He is particularly keen on technology shares right now. The stated aim of Mr Hargreaves is to make Blue Whale the largest fund in the IA Global sector.