SoftBank Group Corp.’s massive $1 billion proposed infusion for Uber Technologies Inc. comes with some major caveats, including that the Japanese megacompany wants to issue a tender offer that is a 30 percent haircut from Uber’s last valuation of close to $70 billion.

The Wall Street Journal reports that SoftBank’s proposed offer, which also comes with two seats on Uber’s board, is slated to end negotiations as soon as next week.

Chinese rideshare behemoth Didi Chuxing, Japan’s billionaire-backed…