Current Attempt in Progress On July 2, 2021, Astrotech Inc. purchased $530,000 of Sain Corp. 4% bonds at a price of 488,688 to yield a market interest rate of 5%. The bonds pay interest semi-annually on July 1 and January 1, and mature on July 1, 2031. Astrotech plans to hold this investment until it matures. At December 31, 2021, which is the year end for both companies, the bonds were trading at 94 (this means 94% of face value).