Not for the first time this year, executives at the world’s biggest oil companies are wondering how much worse the news can get. This week crude prices slid to their lowest levels since the 2008-09 financial crisis — triggered by a rancorous Opec meeting that failed to tackle a global supply glut. The fall has revived investor fears that dividends could be shelved or cut. The suggestion is that “Big Oil” could follow the path of the mining industry, which is dealing with the worst commodities downturn in a decade. Even as miner Anglo American announced on Tuesday that it would withhold payouts for the next 18 months, dividend yields for some energy stocks soared. In London, the yield on Royal Dutch Shell shares topped 8 per cent, rising to within touching distance of historic highs set during market turmoil in August. BP’s dividend yield jumped to 7.7 per cent. Such sharp moves in dividend yield, which measures the payout as a percentage of the share price, reflect the extra returns demanded by investors to hold the shares.