In Hong Kong, trading exceeded HK$100 billion ($12.9 billion) on 24 of the 28 days after the Chinese New Year holiday, according to data from the Hong Kong exchange. Trading on Feb. 28 alone was the highest in a year. Currency and rates trading have also increased during the virus scare.

“The combination of less travel and increased market volatility means that clients are extremely active,” said Michael Blake, Asia CEO of Swiss private bank Union Bancaire Privée. “We have seen consistently high transaction volumes since the start of the year.”

With the fastest expansion of millionaires in the world, Asia is the region where wealth managers from UBS, Credit Suisse Group AG and others are seeking to grow. They’re racing against time to change how they interact with wealthy customers amid the outbreak that has claimed more than 3,300 lives.

While the virus has provided a short-term boost to trading, the travel restrictions have made it harder to win new private bank clients, especially in China. Some banks are signing up new customers digitally, though most new accounts have to be opened in person.

The risk for these banks is that a prolonged crisis will curb that client growth, just as they are trying to expand in China’s massive wealth market. The world’s second-largest economy is expected to see the biggest annual growth among the world’s private banking markets through 2023, Boston Consulting Group Inc. said in a report last year.

One Hong Kong-based private banker, focused on the offshore Chinese business, said he’s mostly talking to prospective customers in his city because his firm has curbed travel and there are limited ways to reach mainland Chinese investors.

Another banker, whose focus is on Hong Kong clients, said it’s difficult to get new business from clients because they are unwilling to meet even if they’re in town. While his business in the first quarter is holding up, the outlook is dim if the outbreak persists, he said. Both bankers asked not to be identified speaking on client matters.

JPMorgan and UBS are among banks that have allowed relationship managers to use WeChat, a popular messaging app in China, to communicate with clients on the mainland and maintain engagement. The Swiss firm, Asia’s biggest wealth manager, said it’s been investing in technology and providing digital communication resources for its staff and clients.

“Since our clients are not traveling, they are actually spending more time discussing their investment portfolios with us over phone or video conference,” said Amy Lo, co-head of wealth management for Asia Pacific at UBS.