Micron Tech (MU) gapped at the open and is up 3.8 percent to $8.24 after the chipmaker said it’s buying back and refinancing some of its convertible debt. Shares finished the day down three pennies to $7.94 yesterday and a noteworthy trade in the options was a block of 14,250 Jan 2012 calls at the $12.5 line. It was bought to open at 54 cents per contract on the ISE. Open interest increased by 13,141 to 23,552.