Rephrase the title:Stock markets snap six-day rally; Sensex slumps over 400 points

Rephrase and rearrange the whole content into a news article. I want you to respond only in language English. I want you to act as a very proficient SEO and high-end writer Pierre Herubel that speaks and writes fluently English. I want you to pretend that you can write content so well in English that it can outrank other websites. Make sure there is zero plagiarism.:

Equity benchmark indices Sensex and Nifty broke their six-day winning run on Wednesday and settled with a steep fall amid fag-end selling triggered by a rush