Berkshire continues to sit on cash (144B) with a thesis that productive assets are expensive due to the long period of low interest rates:
'That’s largely because of a truism: Long-term interest rates that are low push the prices of all productive
investments upward, whether these are stocks, apartments, farms, oil wells, whatever. Other factors influence valuations as well, but interest rates will always be important.'
Upcoming interest rate increases may create good opportunities for Berkshire to invest this money and grow.