Berkshire Hathaway has made an offer to buy remaining 19.9% of the shares which it does not already own in Wesco Financial, for approximately $500m.

Berkshire is supposed to offer Wesco’s other shareholders an amount equal to Wesco’s book value per share, which was about $353 at the end of the second quarter.

Berkshire vice chairman Charlie Munger is CEO of Wesco Financial. Berkshire said it will offer cash and B-class shares for the remaining 19.9% of Wesco.

For Berkshire Hathaway’s cash-and-stock transaction to go ahead, it needs to be approved by majority of Wesco’s independent directors. Berkshire’s board has already approved the plan to approach Wesco’s directors.