Sir, – I am not surprised that with one large foot in Silicon Valley, Irish multibillionaire Patrick Collison would give $7 million of his estimated $17.5 billion fortune to oppose California’s one-time 5 per cent tax to cover social services (“Irish entrepreneur Patrick Collison donated $7m to group opposing California wealth tax,” July 29th). Collison’s donation is dwarfed by that of Google co-founder Sergey Brin who is reported to have given $82 million so far to avoid that tax after recently buying a $42 million mansion on the Nevada side of Lake Tahoe in case it passes. Brin can easily afford both; his estimated wealth is $231 billion.As a Californian currently living in Dublin, I can testify that the phenomenal wealth of San Francisco’s many Silicon Valley billionaires who sometimes live there should have made that city the modern equivalent of Renaissance Florence. Quite the contrary, its cultural institutions are withering or dead and its social services threadbare because, unlike previous tycoons such as Carnegie and Rockefeller, today’s moguls follow their guru Ayn Rand’s views on philanthropy..What can anyone do with such staggering fortunes but buy governments to further increase their riches and to vie with one another for ranking on the Forbes 400 list? That is what inspired the California billionaire tax and why said billionaires are spending a pittance of their net worth in order to torpedo it so they can have yet more and the rest of us less. – Yours, etc,Gray Brechin, Kildare Street,Dublin 2.Sir, – Although Patrick Collison has the right to use his wealth for his own self-interest, he also has an obligation to his community to pay a proportionate part of his wealth to finance social services in Silicon Valley and the wider Californian community, services from which both himself and his company are benefiting.It is not easy for those proposing a wealth tax to counteract the power and resistance of billionaires.Only a few days ago Gary Stevenson retired from his UK campaign for a 2 per cent wealth tax with burnout and disillusionment with the UK wealthy elite. The most recent World Inequality Report (2026) reveals that the most relevant fact emerging from the data is that world inequality remains at very high levels. Today, the top 10 per cent of the global population’s income-earners make more than the remaining 90 per cent, while the poorest half of the global population captures less than 10 per cent of the total global income. Wealth is even more concentrated: the top 10 per cent own three-quarters of global wealth, while the bottom half holds only 2 per cent.Inequality will most likely continue to escalate to very high levels due to the resistance of the super-rich to pay their just share not only of a tax on their wealth but on all forms of taxation.The costs of escalating inequality are clear: widening divisions in society, fragile democracies and a climate crisis borne most heavily by those least responsible. – Yours, etc,Brendan Butler,Drumcondra,Dublin 9.