March 4 (Reuters) - Foreign investors sold Japanese equities for a second straight week last week, marking their biggest net offload since early October as a surge in global bond yields startled investors already concerned about the market's stretched valuation.

Data from Japanese exchanges showed foreigners were net sellers of stocks worth 701.24 billion yen ($6.55 billion) in the week ended Feb. 26, the biggest outflow since the week ended Oct 2.

They sold a net 381.16 billion yen in cash equities markets and 320.1 billion yen worth of derivatives.

Last week, the Nikkei share average plunged 3.5% and the Topix index dipped 3.3%, both marking their biggest weekly decline since the week ended July 31, 2020.

Concerns over rising inflation levels has boosted global bond yields in the past few weeks, dampening the appetite for risk assets.

Yield on the benchmark U.S. 10-year Treasury note touched a one-year high of 1.614% last week.

Meanwhile, Japanese investors sold overseas equities worth 459.1 billion yen last week, marking a seventh consecutive week of net selling, finance ministry data showed. ($1 = 107.1200 yen)

(Reporting by Gaurav Dogra and Patturaja Murugaboopathy; Editing by Rashmi Aich)