A BB-rated company issued 5-year notes at 6% two years ago. The 3-year Treasury is currently at 4%, and the company's credit spread has tightened to 150 bps. If they call the bond today at 102, does it make sense to refinance? Walk me through the math.

一家BB级公司两年前发行了5年期、票息6%的债券。目前3年期国债收益率为4%，该公司的信用利差收窄到了150个基点。如果他们今天以102的价格（提前赎回溢价）赎回债券，重新发债融资是否划算？带我过一下你的计算逻辑。