This is a pre-print of a letter to the Editor published in Nature. The final authenticated version is available online at: https://doi.org/10.1038/d41586-021-03418-1 The letter was written on invitation by the Editor at the occasion of the announcement (on the 27th of October, 2021) by the Dutch Research Council of the results of the first round of the NWO Open Science Fund. In the letter we argue that research funders can do more to foster open science practices. Traditionally funding councils have used mandates (funding requirements) to stimulate open science. And research shows that this is indeed is a very effective way to stimulate open science. The authors believe that in addition to that funders should also recognize and reward open science practices of their applicants. To this end the Dutch Research Council NWO has introduced a dedicated Open Science Fund which aims to recognize and reward researchers who lead in open science by funding projects of up to 50k covering the whole range of open science. The European Commission is even going a step further by including open science practices in the assessment of projects under the new Horizone Europe program. A more elaborate argument found in this letter, can be read in this blog post: M. Cruz, H.L. de Jonge, Beyond mandates, LSE Impact Blog (2020).