Charities providing specialist support services for homeless and vulnerable people across the UK are the first organisations to receive investment from a fund set up by The Big Issue magazine.
A loan of £400,000 will fund Changing Lives to support 150 homeless people in Newcastle and Gateshead.
Changing Lives offers specialist support services for women and families, dedicated recovery centres, temporary and long-term accommodation and employment and volunteering opportunities.
St Mungo's will receive a £125,000 loan to provide upfront funding needed to work with 175 people sleeping rough in London.
The UK charity and housing association works directly with people who are sleeping rough, in hostels and at risk of homelessness across London and South of England.
Support for the charities to help rough sleepers comes at a time when numbers are at an all-time high.
According to official figures, the number of people rough sleeping in England has risen for the seventh consecutive year in a row.
There were 4,751 people counted or estimated to be bedding down outside in autumn 2017, a 15% rise on the year before and more than double the figure recorded five years ago.
Katy Pillai of Big Issue Invest (BII) said: "We are delighted to partner with St Mungo's and Changing Lives to support people with multiple and complex needs to access housing, mental health and addictions support, and employment, education and training opportunities.
"They are both outstanding organisations with an excellent track record and commitment to improving lives."
Stephen Bell, Changing Lives chief executive, added: "We are delighted to be working with BII as an investment partner, not just in respect of the loan but because we believe that we can learn from each other and ultimately inject new ideas as well as investment into the way that we support vulnerable rough sleepers in Newcastle and Gateshead."
Howard Sinclair, chief executive of St Mungo's, said: "The backing of BII is crucial in ensuring we are able to explore innovative options with people who have perhaps reached a very low point in their lives and work with them in their unique recovery journey towards a more positive future."