The building of Lusaka continued through the second half of the 1930s, but progress was slowed by a shortage of funds. The Northern Rhodesia government had hoped to raise money through taxes on the mining companies, but these were mostly registered in the United Kingdom and paid all the tax on their revenues there. The loan taken to cover the project's £400,000 budget was guaranteed by the Beit Trust, but there was no scope for additional infrastructure to be built. The UK launched an investigation into a possible merger of Southern Rhodesia, Northern Rhodesia and Nyasaland in 1938, a prospect which caused private businesses to withdraw investment, fearing that Lusaka would lose its capital status. This left the government as the sole source of funds. Also in 1938, the Northern Rhodesia government commissioned a report by finance expert Alan Pim, to examine the territory's economy. This concluded that despite the relatively high taxes on mining in the territory, the administration (which was already heavily reliant on revenue from mining) was not getting its fair share. Pim also criticised the allocation of housing for Africans in Lusaka, noting that of 10,000 living in the city at that time, only 1,500 were in formal housing. Africans were at that time only permitted to live in the city under temporary work permits, with family members required to remain elsewhere.