Vanguard has agreed to acquire Altruist, a wealth-management technology platform founded in 2018 that provides custody and technology services for independent registered investment advisers, in only the firm’s second acquisition. The deal makes Vanguard a custodian and expands its advisory and wealth-management capabilities under CEO Salim Ramji. Terms were not disclosed, although The Wall Street Journal valued the transaction at roughly $4 billion, citing people familiar with the matter. The agreement was expected to close later in the year subject to customary conditions and regulatory review, with newer reporting describing the transaction as completed. Altruist operates a self-clearing brokerage and integrated adviser software, including its artificial-intelligence-enhanced Hazel platform, and will continue as a separate business under Vanguard. The purchase could deepen ties with roughly 30,000 advisers who already use Vanguard funds and fits a broader industry shift by managers including BlackRock and State Street into advised and affluent clients as fee compression pressures traditional fund management.