Utilize your financial knowledge, give your answer or opinion to the input question or subject . Answer format is not limited.

What is the correct answer for percent change when the start amount is zero dollars $0?
In general, when dealing with quantities like net income that are not restricted to being positive, "percentage change" is a problematic measure. Even with small positive values it can be difficult to interpret. For example, compare these two companies: Company A:  Company B:  At a glance, I think most people would come away with the impression that both companies did badly in Y2, but A made a much stronger recovery. The difference between 99.7 and 99.9 looks unimportant compared to the difference between 100,000 and 40,000. But if we translate those to dollars: Company A: Y1 $100m, Y2 $0.1m, Y3 $100.1m Company B: Y1 $100m, Y2 $0.3m, Y3 $120.3m Company B has grown by a net of 20% over two years; Company A by only 1%. If you're lucky enough to know that income will always be positive after Y1 and won't drop too close to zero, then this doesn't matter very much and you can just look at year-on-year growth, leaving Y1 as undefined. If you don't have that guarantee, then you may do better to look for a different and more stable metric,  the other answers are correct: Y1 growth should be left blank. If you don't have that guarantee, then it might be time to look for a more robust measure, e.g. change in net income as a percentage of turnover or of company value.