Vestmark Inc. agreed to buy Adhesion Wealth Advisor Solutions Inc., looking to expand its portfolio management and trading solutions business in the registered investment adviser, or RIA, market.

Adhesion serves the RIA market with an outsourced investment solution that uses Vestmark's wealth management platform, VestmarkONE. Vestmark also believes this merger will allow it to apply Adhesion's RIA tools to clients such as broker/dealers and wealth managers, among others.

Financial terms of the deal were not disclosed. The transaction is expected to close in the fourth quarter.