Another fast-growing Chinese startup, Beijing Bytedance Technology Co., in recent weeks issued about $300 million in convertible bonds to private-equity firm KKR KKR 1.12% & Co., according to other people familiar with the matter. The company, which owns a popular Chinese news-aggregation app called Jinri Toutiao, was valued at $22 billion in an equity fundraising round in late 2017, according to an individual familiar with that transaction. Spokespeople for Didi, Bytedance and KKR declined to comment. The emerging trend is a result of technology companies' increasing need for cash to fund their expansion at home and abroad, which has involved heavy spending on marketing and other costs to acquire customers and fend off rivals. Selling convertible securities allows companies to raise capital with less dilution to existing shareholders, while giving buyers of the instruments an opportunity to reap additional gains if and when the debt converts into stock down the road.