Interactive Brokers shares could double by late 2031 only if earnings per share double and the stock retains its current roughly 29-times forward-earnings multiple, according to a Motley Fool analysis; at a multiple of 20, the five-year gain would be about 38%.
In the first half of 2026, Interactive Brokers’ earnings per share rose 30% year over year, net interest income 20% and commission revenue about 25%. Net interest income accounted for 57% of 2025 net revenue. The company estimates a 0.25-point change in U.S. dollar rates would alter annual net interest income by about $81 million either way. Its pre-tax margin is already roughly 77%, leaving little room for growth from further margin expansion.
At the end of August, Interactive Brokers had 5.46 million client accounts, up 35% year over year, and $962.8 billion in client equity. The analysis says accounts would need to reach about 11 million by 2031—around 15% annual growth—if average assets per account stayed flat. It cautions that margin loans, which stood at $101.5 billion in August after reaching $108.5 billion in June, could shrink in a difficult market.
