WellCare Health Plans Inc. said late Tuesday it had agreed to buy privately held Meridian Health Plan of Michigan, Meridian Health Plan of Illinois, and MeridianRx, a pharmacy benefit manager, for $2.5 billion in cash. The transaction is expected to close by the end of the year, subject to closing conditions and regulatory approvals, WellCare said in a statement. Through the deal, “WellCare will diversify its Medicaid portfolio through the addition of Michigan, where Meridian has the No. 1 Medicaid market position; deepen its Medicaid business in Illinois; and acquire an integrated (pharmacy-benefit manager) platform,” the company said in a statement. Shares of WellCare rose 0.2% in late trading after ending the regular session up 0.5%.