KMART’S BIGGEST MARKDOWN: Kmart Corp. shares lost more than one-fifth of their value in New York Stock Exchange trading Friday, as concerns about the Troy, Mich.-based discounter’s ability to extract itself from a growing liquidity crisis intensified. Shares opened at $4 and hit a 34-year low of $2.99 in intraday trading before rebounding to close at $3.30, down 90 cents. Volume, at more than 45.7 million shares, was seven times the average levels. Kmart’s 52-week high of $13.55 was reached just five months ago, on Aug. 8, and it traded at more than $15 as recently as July 1999 and at above $20 a year earlier. Kmart’s market capitalization at the end of last week stood at $1.65 billion. Moody’s Investors Service downgraded about $4.7 billion of Kmart debt on Friday, lowering senior unsecured debt, medium term notes, issuer rating and senior implied rating to B2 from Ba2.