By Ellen Chang Billionaire Warren Buffett added shares of companies during the market downturn. Billionaire Warren Buffet has been acquiring stocks on the dip during the recent market downturn and bulking up his stakes in oil companies such as Occidental ( (OXY) – Get Occidental Petroleum Corporation Report). Through the end of 2021, Berkshire Hathaway ( (BRK.A) – Get Berkshire Hathaway Inc. Class A Report had amassed a large amount of cash, increasing speculation on the CEO’s plans for the company. The conglomerate had $146.72 billion and after buying up insurance company Alleghany Corp ( (Y)…