Grant applications with overlapping deadlines: listing other grants one has applied for? Often, when applying for grants, one is asked to mention other grants one has received, one has applied for, and one is going to apply for. Whereas the first point is simple, how should one handle the second and third point (other grants one has applied for, and is planning to apply for)?

My case is that there are two big grants I would like to apply for, both offering enough money to keep me going for a number of years. For both grants one has to apply in spring, and the decision is made and announced towards the end of the year. The grant would be for research and salary starting from next year.

Both grants ask the applicant to list which other grants they have applied/are going to apply for. What is the effect of listing the other big grant, if both grants can cover 100% of the costs? Does it decrease the chance to be accepted, does it affect the money that is paid out (in case of variable grants)? In general, is there a benefit of listing the other grant, or is there a risk in doing so? Are there retributions when not listing other grants one has applied for, or even applying despite not saying so during another grant application?
This is how I do it and perhaps this could work for you too. Usually I list the applications that I have already submitted and that are under evaluation and I specify the budget size and what the funding will be used for (PhDs, postoc, own salary) and in particular I specify for for each of them if it is related or not to the current application. I also mention somewhere what is the priority, e.g. that if both the current application and one of those that I have applied for already -and that is on the same topic - will be funded, then one of the two (usually the smaller in terms of budget or prestige) will be not be maintained or will be withdrawn. It's a bit difficult to list applications that you plan to do but haven't written yet, because in principle you might not manage to submit them. So usually I avoid doing that unless I am 100% sure I will submit it. I also think it's pretty normal to submit similar project ideas to different councils and in different formats, and this simply shows that you are active in the hard job of fund raising so for me is a positive sign. In general it's always good to be transparent when it comes to applications.