The news: Bank of New York Mellon, the world’s largest custodial bank, has reportedly proposed a merger with its smaller competitor Northern Trust, per The Wall Street Journal. It hasn’t submitted a formal proposal, but if the merger moves forward, it would be what experts consider a “monster deal.”

Ripple effects: The merger would shake up the banking industry if a formal proposal is accepted then approved for multiple reasons.

• The combined entity would dominate the custody banking space, with massive scale and operational reach, pressuring smaller competitors to either consolidate or find niche advantages.