UPDATE 2-US high-grade company debt sales rise to $33 bln

(Recasts first paragraph, adds quote, weekly high yield debt total at highest this year)

NEW YORK, May 9 (Reuters) - U.S. investment-grade corporate bond sales rose its highest in two weeks as interest rate cuts by the Federal Reserve and the need for finance companies to bolster balance sheets is spurring new sales.

Investment-grade corporate debt rose to a weekly total of more than $33 billion this week, the biggest week since a record $40 billion was sold two weeks ago, according to Thomson Reuters data.

"The worst may be behind us as evidenced by improving borrowing conditions and more sales," said Richard Peterson, director of capital markets at Thomson Reuters in New York. "We're seeing willing buyers of paper."

U.S. companies, including Citigroup Inc. (C.N: Quote, Profile, Research) and GlaxoSmithKline Capital Inc, a unit of pharmaceutical company GlaxoSmithKline PLC (GSK.L: Quote, Profile, Research) (GSK.N: Quote, Profile, Research), sold corporate debt totaling more than $36 billion, including $3.1 billion of high-yield debt, the highest weekly total this year, versus about $30 billion in total debt the previous week, according to Thomson Reuters data.

GlaxoSmithKline Capital on Tuesday sold $9 billion of debt in a four-part deal, while Citigroup sold $3 billion in 10-year notes on Monday. (Reporting by Walden Siew; Editing by Theodore d'Afflisio)