KOLs on the X platform often simplify the rise in M2 or the weakening of the US dollar as a signal for a surge in Bitcoin, but in reality, the relationship between the two and Bitcoin is not linear, but rather a conditional correlation affected by time lag and market cycles. Data from the past 12 months shows that Bitcoin has a correlation of 0.78 with the 84-day lagged M2 level, a correlation of 0.77 with the 84-day forward M2, and an inverse correlation of -0.58 with the US Dollar Index (DXY). The negative correlation coefficient between M2 and DXY is -0.71. However, this correlation is only reflected in the medium to long term trend. On a daily basis, the correlation between Bitcoin and the returns of M2 and DXY is only 0.02 and 0.04, respectively. The so-called "dollar rises and Bitcoin falls" is not a one-day phenomenon. The lag effect is a key variable: Bitcoin yields have the highest correlation with the M2 trend 6 weeks ago (42 days) (0.16), and a correlation of -0.20 with the DXY trend 1 month ago (33 days). To put it figuratively, M2 is like a slow-moving gravitational pull, taking weeks to show its effects; DXY is like an accelerator, applying pressure quickly, and the two rarely work in sync. The market divergence in 2025 further highlighted this conditionality: before the Bitcoin peak on October 6, its correlation with M2 was as high as 0.89, with the 84-day forward M2 accurately tracking the price path; after the peak, the correlation reversed to -0.49, with M2 continuing to rise but the price diverging, while the inverse correlation with DXY of -0.60 remained stable. The 180-day rolling correlation data is more intuitive: it reached a peak of 0.94 on December 26, 2024, fell to -0.16 on September 30, 2025, and was -0.12 on November 20, reflecting that the M2 leading effect was significant in the bull market, while the correlation weakened in the later stage of the cycle due to the strengthening of the US dollar and position adjustments. The core logic lies in the division of roles between the two: M2 acts as a slow-trend compass, only driving Bitcoin to begin a multi-month-long rise when the US dollar is stable or weakening; DXY, on the other hand, dominates short-term fluctuations, suppressing rises and deepening corrections when it strengthens. When M2 and DXY move in the same direction, the Bitcoin trend is clear and smooth; when they conflict, previously effective lag strategies become ineffective, and the correlation collapses. Be wary of the misconception of fixed lag values: the 84-day window performs well in bull markets, but its effectiveness declines after the dollar strengthens at the end of 2025, and the optimal lag period fluctuates with market changes. In practice, the yield slopes of M2 and DXY should be monitored over a period of 1-3 months to ensure that they are aligned before referring to the M2 indicator. At the same time, the lagged value should be allowed to fluctuate within a reasonable range rather than being locked into a single figure. Bitcoin's price movement is not determined by a single variable; the combined effects of M2 and the US dollar need to be considered in conjunction with the cyclical phase and lag effects. Instead of blindly relying on simple chart overlays, it's better to build a dynamic framework: track the M2 trend when the dollar is stable, and focus on short-term pressures when the dollar fluctuates, which is more likely to capture market signals more accurately.KOLs on the X platform often simplify the rise in M2 or the weakening of the US dollar as a signal for a surge in Bitcoin, but in reality, the relationship between the two and Bitcoin is not linear, but rather a conditional correlation affected by time lag and market cycles. Data from the past 12 months shows that Bitcoin has a correlation of 0.78 with the 84-day lagged M2 level, a correlation of 0.77 with the 84-day forward M2, and an inverse correlation of -0.58 with the US Dollar Index (DXY). The negative correlation coefficient between M2 and DXY is -0.71. However, this correlation is only reflected in the medium to long term trend. On a daily basis, the correlation between Bitcoin and the returns of M2 and DXY is only 0.02 and 0.04, respectively. The so-called "dollar rises and Bitcoin falls" is not a one-day phenomenon. The lag effect is a key variable: Bitcoin yields have the highest correlation with the M2 trend 6 weeks ago (42 days) (0.16), and a correlation of -0.20 with the DXY trend 1 month ago (33 days). To put it figuratively, M2 is like a slow-moving gravitational pull, taking weeks to show its effects; DXY is like an accelerator, applying pressure quickly, and the two rarely work in sync. The market divergence in 2025 further highlighted this conditionality: before the Bitcoin peak on October 6, its correlation with M2 was as high as 0.89, with the 84-day forward M2 accurately tracking the price path; after the peak, the correlation reversed to -0.49, with M2 continuing to rise but the price diverging, while the inverse correlation with DXY of -0.60 remained stable. The 180-day rolling correlation data is more intuitive: it reached a peak of 0.94 on December 26, 2024, fell to -0.16 on September 30, 2025, and was -0.12 on November 20, reflecting that the M2 leading effect was significant in the bull market, while the correlation weakened in the later stage of the cycle due to the strengthening of the US dollar and position adjustments. The core logic lies in the division of roles between the two: M2 acts as a slow-trend compass, only driving Bitcoin to begin a multi-month-long rise when the US dollar is stable or weakening; DXY, on the other hand, dominates short-term fluctuations, suppressing rises and deepening corrections when it strengthens. When M2 and DXY move in the same direction, the Bitcoin trend is clear and smooth; when they conflict, previously effective lag strategies become ineffective, and the correlation collapses. Be wary of the misconception of fixed lag values: the 84-day window performs well in bull markets, but its effectiveness declines after the dollar strengthens at the end of 2025, and the optimal lag period fluctuates with market changes. In practice, the yield slopes of M2 and DXY should be monitored over a period of 1-3 months to ensure that they are aligned before referring to the M2 indicator. At the same time, the lagged value should be allowed to fluctuate within a reasonable range rather than being locked into a single figure. Bitcoin's price movement is not determined by a single variable; the combined effects of M2 and the US dollar need to be considered in conjunction with the cyclical phase and lag effects. Instead of blindly relying on simple chart overlays, it's better to build a dynamic framework: track the M2 trend when the dollar is stable, and focus on short-term pressures when the dollar fluctuates, which is more likely to capture market signals more accurately.