US oil major Chevron has decisively taken the long-awaited step to exit Caltex Australia, selling its 50 per cent stake for $4.62 billion in the country's biggest-ever block trade.

As revealed by Street Talk on Friday afternoon, Chevron, which owned 50 per cent of the fuels marketer and refiner, sold its 135 million shares at $34.20, a 9.7 per cent discount to the closing price on Friday of $37.88.

Chevron will continue to supply fuel to Caltex's retail and franchise network of service stations. Credit:Glenn Hunt

The sale was underwritten solely by Goldman Sachs, which by 5pm on Friday had already placed more than half the stock with a range of domestic and international investors, at an average price higher than $34.20.