The first thing that looks wrong is the overuse of capitals. It would be more natural to say 'I analysed' or 'I did analysis of', and 'bonds' should be plural. I have no idea what 'zero-coupon' means - is it financial jargon? Do you want to make it 'pithy'? That's not normally a positive attribute!

"I analysed the term structure of interest rates on zero-coupon bonds". (Can substitute 'on' with 'for') "Interest on principal", not "interest of principal". The interest amount is always calculated upon a base amount. This applies to "interest rate" as well, because that is "rate of interest". I have no idea how to make such a dry subject sound (or look) pithy. "Pithy“= terse, concise. I am not aware of a negative connotation. Pithiness implies a certain economy of language and precision of delivery. pithy (adj.) early 14c., "strong, vigorous," from pith + -y. Meaning "full of substance or significance" is from 1520s; literal meaning "full of pith" not attested until 1560s. pith (n.) Old English piþa "pith of plants," also "essential part," figurative sense was in Old English. "Pith helmet"