Lucy Nicholson/ReutersHere is what you need to know: Warren Buffett says stocks are "on the cheap side" when measured against today's interest rates. "If interest rates were at seven or eight percent, then these prices would look exceptionally high," the Berkshire Hathaway chairman told CNBC. Berkshire bought more Apple shares. Buffett said he raised his stake in Apple this year to about 133 million shares, more than double his holding as of December 31. Japan's SoftBank Group nears an investment in the US office-sharing startup WeWork.