Wirecard's logo can be seen on a smartphone held in front of a stock market chart.

SoftBank will invest 900 million euros ($1 billion) into German fintech firm Wirecard, as part of a strategic partnership on digital payments.

Wirecard said Wednesday that it will raise the capital by issuing convertible bonds with a maturity of five years, selling them exclusively to SoftBank.

The notes will convert to an almost 6% stake in the firm. The deal is still subject to the approval of Wirecard shareholders.

Shares of Wirecard jumped more than 9% on the news.

It's part of a tie-up between the two on digital payments, according to Wirecard. SoftBank will help the firm — which ousted Commerzbank from Germany's blue-chip DAX index last year — expand to Japan and South Korea.

"In SoftBank we have found a partner that shares both our passion for new technologies and drive to spearhead the latest innovations, all on a global scale," Wirecard Chief Executive Markus Braun said in a statement.

"In addition, through this potential partnership, we will expand our reach and products to the East Asian markets, thereby further strengthening our position in Asia."