The failed Chinese bicycle app Ofo, which burned through $1.5 billion in venture capital, convinced many investors that bike sharing is a horrible business. But Hellobike, backed by Jack Ma’s Ant Financial, is trying to prove the skeptics wrong as it looks to raise significant new funding.

Hellobike is seeking a valuation of $4 billion—nearly double its previous price tag of $2.2 billion last year—in its discussions to raise hundreds of millions of dollars, people familiar with the matter said. But getting new investors to agree to a lofty valuation is challenging.