In the latest evidence of how Wall Street is seeking to broaden its sources of funds, Goldman Sachs Group Inc. is weighing whether to launch an Internet banking operation, according to people familiar with the situation.

If Goldman goes ahead, the new unit will seek deposits that can be used to fund various businesses now that Goldman is a bank-holding company. The possible online bank hasn't been named yet, and many details of its operating plans are undecided. It is likely to offer a range of savings products, such as certificates...