The changes take effect today with the higher lending limits initially available for applications submitted through mortgage brokers.
For capital repayment mortgages at 90% LTV, the maximum loan has increased from £750,000 to £775,000, although the limit for flats remains £750,000.
At 85% LTV, the maximum has risen from £2m to £3m, with a £1m limit for flats, while the maximum at 75% LTV has increased from £3m to £5m, with a £3m limit for flats.
HSBC has also increased its maximum interest only loan at 75% LTV from £2m to £3m, with borrowing on flats capped at £2m.
Alongside the criteria changes, HSBC has reduced rates across its first time buyer, purchase and remortgage ranges.
First time buyer changes include a two year 90% LTV fee free product at 5.06%, down by 0.03%, and a five year equivalent at 4.93%, down by 0.05%.
Its five year 95% LTV fee free first time buyer product has been reduced by 0.09% to 5.24%.
For purchases, HSBC has cut its five year 90% LTV product with a £999 fee by 0.07% to 4.82%. The Premier equivalent has also fallen by 0.07% to 4.79%.
Remortgage reductions include a two year 85% LTV fee free product at 5.17%, down by 0.20%, and a five year 90% LTV fee free product at 5.23%, down by 0.14%.
The five year 85% LTV Premier remortgage product with a £999 fee has been reduced by 0.12% to 4.89%.
Oli O’Donoghue, head of mortgages and savings at HSBC UK, said: "Our enhanced lending limits will open up new opportunities for our customers by increasing the properties available to them.
"This could mean they are able to buy a property with their dream kitchen, an additional bedroom or in another area.
"The change reflects our desire to help customers achieve their homebuying ambitions, whichever step on the property ladder they find themselves on."
