Facebook shares posted their biggest daily gain in nearly two years as chief executive Mark Zuckerberg fended off questions from US senators on how the world's largest social network might be regulated more closely.
Zuckerberg repeated apologies made on Monday for a range of problems that have beset Facebook, from data privacy to foreign attempts to influence US elections, but the 33-year-old internet mogul managed to deter any specific talk about new laws and made no new promises.
