The Earned Income Credit STARTS at $40,300-ish. You don't immediately get the full amount at that income.<a rel="nofollow" target="_blank" href="https://www.irs.gov/pub/irs-prior/i1040gi--2018.pdf#page=53">https://www.irs.gov/pub/irs-prior/i1040gi--2018.pdf#page=53</a>
This link provides additional qualifying information on the EIC:
https://ttlc.intuit.com/replies/3299933