On Thursday's "Ask Halftime," our traders answered questions from CNBC Pro subscribers about stocks and ETFs during this market volatility, including whether to buy, sell or hold specific names. Jenny Harrington of Gilman Hill Asset Management says that Star Bulk Carriers will, to some degree, be affected by the slowdown of iron ore demand. However, she adds, the shipping company has a strong formula for generating cash. Josh Brown of Ritholtz Wealth Management adds that Encore Capital Group is a new position of his. He is interested in the debt collection company as credit card balances expand. Finally, Karen Firestone of Aureus Asset Management recommends buying less than a full position in Twilio and suggests watching the company's next few quarters.