Credit card companies and banks are getting serious—or at least more curious—about the potential of bitcoin, making an increasing number of investments in startups involved with the digital currency. American Express late last week confirmed it participated in a $12 million Series A funding round for Abra, a service that makes it easier to send money between countries using the technology underlying bitcoin, called blockchain. Cross-border money transfers are viewed as an area where the technology could be particularly useful, given that conventional methods are costly and slow. The move by AmEx—its first investment in the digital currency—underscores how traditional financial institutions are at least taking initial steps toward understanding and incorporating bitcoin into some aspects of their business. However, they’re still wary about diving in headfirst, due to an unclear regulatory environment and a lack of mainstream interest. Blockchain startup Chain raised a $30 million Series B round last month, with big names like Visa, Nasdaq, and Citi taking part in the investment. Chain also partnered with Nasdaq for a pilot program in which private shares could be traded using blockchain technology. Another startup, R3CEV, has partnered with 22 of the biggest banks in the world, including Bank of America, Citi, BNY Mellon, Morgan Stanley, Barclays, BBVA, Goldman Sachs, and JPMorgan. Not much is known about R3CEV, but it’s focused on understanding the different uses of bitcoin and blockchain in order to find the best applications for the technology in the banking world.