On Thursday’s “Ask Halftime,” traders answered questions from CNBC Pro subscribers about stocks, bonds and exchange-traded funds during this period of heightened market volatility, including whether to buy, sell or hold individual names. Cerity Partners’ Jim Lebenthal shared why the Vanguard S & P 500 ETF can be a good place to start for those looking to invest in the stock market. Stephanie Link of Hightower Advisors explained why Fortinet is a top investment in the cybersecurity sector.