Jan 28 (Reuters) - Citigroup Inc has hired four Black-owned firms to distribute a $2.5 billion bond issuance to investors, as part of its work to promote racial equity in the capital markets and broader financial services industry, the bank said on Thursday. The firms included Blaylock Van, CastleOak Securities, Global Oak Capital Markets and Loop Capital Markets, Citi said in a statement. “Minority-owned broker dealers, Black-owned firms in particular, have historically and largely been shut out of the capital markets. Yet, recent data shows that investing in these firms is good business,” Citi Chief Financial Officer Mark Mason said. Mason is one of the industry’s most senior Black executives. Last year, the Wall Street bank said it would set aside more than $1 billion to support initiatives that help close the racial wealth gap and increase economic mobility for people of color. In September, Verizon Communications Inc tapped Loop Capital and another Black-led firm, Siebert Williams Shank, as lead underwriters of a $1 billion green bond offering. (Reporting by Noor Zainab Hussain in Bengaluru and Imani Moise in New York; Editing by Shinjini Ganguli)