From the Document: "By August 15 of each year, the Congressional Budget Office [CBO] is required to issue a report that provides estimates of the limits (often called caps) on discretionary budget authority that are in effect for each fiscal year through 2021. CBO also must report whether, according to its estimates, enacted legislation for the current fiscal year has exceeded those caps. If so, a sequestration (that is, a cancellation of budgetary resources) would be required. In CBO's estimation, a sequestration will not be required for 2018. However, the authority to make such a determination--and, if so, exactly how to cut budget authority--rests with the Administration's Office of Management and Budget (OMB). That agency reported in April that appropriations for 2018 had not exceeded the caps. No appropriations have been enacted since then."
Congressional Budget Office: https://www.cbo.gov/