What is 90/10 investment rule of world's 10th-richest man Buffett?

The world's 10th-richest man, Warren Buffett, recommends allocating 90% of investments to a low-cost S&P 500 index fund and 10% to short-term government bonds. He believes equities can deliver higher returns than bonds or cash over the long term. The bond allocation provides liquidity and helps reduce overall portfolio risk during market downturns, though losses remain possible.