Currently, "the UK will pay Mauritius an annual average of £101 million for 99 years in 2025/26 prices, totalling around £3.4 billion" [1]. But the islands are probably worth north of $20bn to the U.S.
If the U.S. bought the islands for $20bn and then had the UK pay it $135mm/year for 99 years, it would effectively get them for $15bn–a good deal. Mauritius, meanwhile, would get enough money to launch the entire World Bank climate-resiliance portfolio ($5 to 6bn for stuff like coastal protection, climate proofing Port Louis, et cetera); build the series of mini reservoirs and leak repair projects proposed for water resilience ($250mm); complete the road improvements they've been discussing with India ($3bn) and enact their energy-transition roadmap to get to 60% renewables (from 80% fossil fuels today) by 2030 ($2bn).
That still leaves $10bn, enough to endow a research university ($2.5bn), give every obese Mauritian the option of going on GLP-1s (sourced from India, where patents expire this year) and set up a nationwide system of diabetes treatment and prevention centers ($2bn). Then set up a sovereign wealth fund with the remaining $7 to 8bn, paying out 3% a year or $189/citizen/year, this amount representing about 5.5% of median income (similar to ~$2,500/person/year in America).
This materially improves the lives of Mauritians while safeguarding their long-term prospects without paying a cent to overseas financiers for e.g. debt reduction in exchange for something of dubious value to Mauritius as it is.
[1] https://commonslibrary.parliament.uk/research-briefings/cbp-...