The following lenders have adopted the BSA Mortgage Instructions:
- Astra Mortgages, a trading name of Yorkshire Building Society
- Bath Building Society
- Beverley Building Society
- Buckinghamshire Building Society
- Cambridge Building Society
- Chorley Building Society
- City of Derry Building Society
- Cumberland Building Society
- Earl Shilton Building Society
- Ecology Building Society
- Hanley Economic Building Society
- Hinckley and Rugby Building Society
- Ipswich Building Society
- Leek United Building Society
- Loughborough Building Society
- The Mansfield Building Society
- Marsden Building Society
- Melton Mowbray Building Society
- mbs Lending Ltd
- Newbury Building Society
- Newbury Mortgage Services
- Newcastle Building Society
- Norwich & Peterborough Building Society, a trading name of Yorkshire Building Society
- Nottingham Building Society
- Penrith Building Society
- Stafford Railway Building Society
- Teachers' Building Society
- Tipton & Coseley Building Society
- West Bromwich Building Society
- West Bromwich Mortgage Company Ltd