PayPal is following its investment in micro-investing app with a direct link, vastly expanding the app's addressable market.

Bloomberg News

Acorns, which is aimed at acquiring new investors and underserved markets, rounds up users' credit and debit card payments to the nearest dollar. It invests that difference in the stock market.

When consumers log into their PayPal account, they will be able to link to their Acorns account from the PayPal home screen. Users will be able to transfer funds, monitor investments, make withdrawals and manage their investment accounts from the PayPal site and mobile app.

The 5-year-old company has 2.4 million accounts, and charges $1 per month to maintain an account. The link to PayPal could greatly expand that reach, given PayPal has 218 million active customer accounts.

PayPal invested about $30 million in Acorns in 2016.