I have an Interactive Brokers margin account, but so far, I haven't been using the margin; I'm considering doing so.

According to <https://www.interactivebrokers.com/en/index.php?f=18069>, their interest rate below $25k (which is the range I'm considering initially) is 3.42%. If I consider the historical stock market data from 1986-2016 from <https://www.thebalance.com/stock-market-returns-by-year-2388543>, I determine an arithmetic mean of 11.8% and a geometric mean of 10.4%.

Therefore, *assuming* that the last 30 years are indicative of the returns I would get in my time horizon (which could be 5 years or so), it seems very attractive to invest with margin as then I would still earn 6-7%.

Does this reasoning make sense? Are there factors I haven't considered?