Generating ten thousand dollars per month in passive investment income—equaling one hundred twenty thousand dollars annually—requires a substantial capital base determined entirely by your portfolio's average dividend or distribution yield. Assuming a conservative, balanced dividend yield of 4 percent, an investor would require a total portfolio principal of approximately $3,000,000. If you target a higher dividend yield of 6 percent through a mix of blue-chip equities and income funds, the necessary capital decreases to $2,000,000, whereas an aggressive 8 percent yield demands $1,500,000. Achieving this income safely requires careful diversification, focusing on financially stable corporations with robust free cash flows and sustainable long-term payout ratios.