Fixed-income investors lack a good mobile tool for building and analyzing bond portfolios. We want an iOS app that lets users browse a large catalog of corporate and government bonds (data from our central warehouse), search and filter instantly by yield, duration, rating, maturity, issuer, currency, and more, and construct portfolios. As users add or remove bonds, the app should immediately show portfolio-level metrics: weighted-average yield to maturity, duration, and a breakdown of credit quality. Include a cash-flow calendar that visualizes upcoming coupon payments. The results list must feel instant even with thousands of rows and a dozen+ filters/sorts, so the list implementation needs to be highly efficient. Use an MVP architecture and integrate our existing Objective-C calculation modules.