They are still making money on the investment but that 500 million was the first investment in 2019. They also invested another 901 million in early 2021 for a total investment of 1.4 billion.Ford had invested $500MM in Rivian in 2019. For that, they received approx. 102MM shares or about $5 per share. Even at $25 per share, they made a 400% profit on their initial investment.
Ford is not in the business of investing. They do not want to be holding large interests in other companies unless they have business dealings with them. Owning an extremely volatile stock only hurts them as they do not want massive gains one quarter and massive loss the next. Ford has $21 billion in cash, they are not selling Rivian to raise funds.