As assets under management grow, costs typically do not increase by the same proportion. As revenues grow more than expenses, profits go up. The fund can then enable a drop in expense ratios.
This AMC has announced a roadmap for a drop in expense ratios of its funds. It's not the first time it has done it. When Quantum Long Term Equity Fund was launched in 2006, it carried an expense ratio of 2.25%. It is currently 1.25%.
The expense ratio of the Quantum Tax Saving Fund will be the same as that of the Quantum Long Term Equity Fund, irrespective of the AUM level.