Israel's markets regulator said on Monday he will propose regulation to ban companies based on bitcoin and other digital currencies from trading on the Tel Aviv Stock Exchange (TASE).Shmuel Hauser, the chairman of the Israel Securities Authority (ISA), told the Calcalist business conference he will bring the proposal to the ISA board next week. If approved, it would be subject to a public hearing and then the TASE bylaws would need to be amended."If we have a company that their main business is digital currencies we would not allow it. If already listed, its trading will be suspended," Hauser said, adding the ISA must find the appropriate regulation for such companies.Bitcoin plunged by 30 percent to below $12,000 on Friday as investors dumped the cryptocurrency after its sharp rise to nearly $20,000. It recouped some losses to trade above $14,000 on the Bitstamp platform, down 9 percent on the day."We feel that the prices of bitcoin behave like bubbles and we don't want investors to be subject to that volatility and uncertainty," Hauser said. "There is an importance to signal to the market where things are... Investors should know where we stand."Earlier this month, Hauser had said bitcoin-based companies would not be included in TASE indexes and that there was a need for a suitable regulatory framework for such instruments given that the global market value of all digital currencies grew in 2017 to $300 billion from $18 billion.The proposal will likely be the last for Hauser, who will step down next month after 6-1/2 years as ISA chief."But once it's on its way it will continue to be pursued," said Hauser, who will be replaced by Anat Guetta.He said he hopes she will promote easing capital gains taxes and focus on regulatory enforcement.