Dispersive effects inD0-D¯0mixing

We estimate the size of dispersive effects in ΔC=2 interactions and find that they represent in fact the dominant components of $D^0$-D${¯}^0$ mixing. The box diagram is suppressed by several orders of magnitude due to the small values of light-quark masses. Crucial to this argument is a discussion of how the Glashow-Iliopoulos-Maiani mechanism works in the dispersive sector.