For all the sci-fi promises about blockchain transforming finance, the reality will be more mundane as thousands of ordinary instruments quietly move to digital ledgers. On Wednesday, it was money market funds.

Bank of New York Mellon Corp. and Goldman Sachs Group Inc. are collaborating to use blockchain technology to maintain an ownership record of money market funds.

The Wall Street banking giants are joining to a growing roster of global financial firms to offer tokenized versions of assets.