The belief that sends people to fix the wrong thing is that they were refused for being blacklisted
Almost everybody whose mortgage application is declined thinks of that first.
Then they check their credit report, find nothing wrong, and are no wiser.
Because credit history is only one of four groups of reasons, and it is not even the most common one.
The most common is repayment capacity, which is pure arithmetic and can be worked out before applying at all.
Banks rarely give itemised reasons, which leaves people feeling there is no way to know.
But not being told is not the same as there being no reason, and nearly every reason can be found with information you already have.
Group one: debt to income, the leading reason
The bank is not asking what you earn. It is asking whether, after all existing debt, there is enough left to carry a mortgage.
You can work this out yourself in ten minutes.
Step one, add up the monthly payments on every debt you have: car, credit cards, personal loans, instalment purchases.
For credit cards and revolving credit, banks usually do not count only what you actually pay, but a proportion of the outstanding balance according to their own rules.
Step two, add the mortgage payment you are about to ask for to that total.
Step three, divide by the monthly income you can prove. The operative words are can prove, not the income you actually have.
The result is your debt to income ratio.
There is no single ceiling that applies to everybody. It varies with income level, with occupation, and with each bank's policy.
Higher earners are usually allowed a higher ratio, because what remains after the payment still supports a life.
So rather than hunting for a ceiling figure, ask a bank directly, before applying, roughly what limit is possible with this income and these debts.
That question is free and requires no application.
Why the amount is so much less than expected
Most people overestimate themselves for four reasons.
Counting income that cannot be proved: side income, cash, or work with no documentation.
What counts is what is documented and passes through a bank account.
Forgetting debts that do not feel like debts: a phone on instalments, furniture on instalments, or a facility you co-signed for somebody else.
A co-borrower counts in full rather than by half, as explained in whether a co-borrower can walk away.
Calculating the instalment on a promotional interest rate, when the bank assesses capacity at a higher rate to allow for future increases.
Forgetting that unused credit cards still count, because they are credit you can reach.
Together these four can put a million baht or more between the figure in somebody's head and the figure the bank sees.
Group two: credit history
This group is rarer than people fear, but slowest to fix when it does apply, because it requires waiting.
What to look at is not whether there was ever an arrear, but the pattern and how recent it is.
One late month two years ago followed by perfect payment reads very differently from a year of alternating late and on time.
How to obtain your own report and what to read first is in how to get and read your credit bureau report.
What to remember is that individual data stays for thirty six months, which means time is working for you every month that passes.
Group three: the security itself
This group surprises people most, because the problem is not with the borrower at all.
The bank values the property below the agreed price, so the approved amount falls short and the buyer has to find the difference in cash.
Why that gap exists is explained in assessed value against market price.
A house built differently from the approved drawings, or without a permit, which leaves the security exposed to a correction or demolition order.
Land with no access to a public way, or with access that was never registered as a servitude.
A house so old that its remaining life is shorter than the loan term, which is why old timber houses attract low limits.
Property in an area that particular bank does not lend on, because some banks restrict areas by policy, which has nothing to do with you.
That last explains why the same person is approved by another bank without changing anything.
Group four: income stability and documents
Recently changed jobs, since banks usually want a period of service to see continuity.
Self employed with income that never passes through an account, which is fixable but takes time, because the account has to show consistent receipts.
Income that swings widely, such as commission or seasonal work, which banks usually average backwards rather than taking the best month.
Documents incomplete or inconsistent, such as a name spelled differently across papers, or two different addresses.
The last sounds trivial but slows everything down and sometimes ends it.
The LTV rules that change with policy
The loan to value limit is set by the Bank of Thailand and adjusted according to economic conditions.
A temporary relaxation allowing borrowing up to the full value of the security has been in force from 1 May 2025 to 30 June 2026.
The word to read is temporary.
When a measure ends, the ordinary rules return, with different ceilings by property price and by which contract number it is.
The problem that actually happens is somebody who planned while a measure was in force and applied after it ended.
They find they need a deposit they never budgeted for, and the deal fails although nothing about them changed.
So the question to ask is which rule applies on the day you actually apply, and which contract number yours counts as.
Anybody who already owns one house and is still paying for it should ask this particularly.
Four things not to do after a refusal
Do not fire applications at several banks at once, because frequent credit applications in a short window are a signal lenders read.
Find the reason first, then choose the single most suitable bank.
Do not take informal credit to raise the deposit, because it raises your debt to income immediately and makes approval less likely than before.
The risks of informal lending are covered in what you are signing when you pledge a title deed.
Do not buy a car or take on other large instalments while a mortgage application is still intended.
Do not close the deposit account your income runs through, because that account history is the income evidence the bank looks at.
A six month plan that works
If you were refused and intend to apply again, do it in this order.
Month one, find the reason. Get your own credit report, calculate your debt to income, and ask the bank what it valued the property at.
Those three between them identify which group the problem sits in.
Months one to two, clear the small debts, starting with those whose monthly payment is high relative to the balance remaining.
Clearing three small debts reduces debt to income more than people expect.
Month two, close unused facilities and get written confirmation of closure from the institution.
Months two to five, run the account consistently, with income arriving in the same account every month.
Self employed people gain most from this, and it is the part that takes time, so start earliest.
Month five, check the credit report again to confirm the closures have actually reached the system.
Month six, apply again, choosing the bank that suits your occupation and the property's location rather than the one advertising the lowest rate.
And before applying, ask once more which LTV rule is in force that day.
Frequently asked questions
The bank gave no reason. How do I find out?
Nearly all of it comes from three things: your own credit report, your debt to income calculation, and the bank's valuation of the property. Those cover most of the reasons that actually occur.
Can I just apply to another bank straight away?
You can, but not to several at once, because frequent applications in a short window are a signal lenders read. Find the reason first, then pick the single most suitable bank.
Why can somebody on the same salary borrow more?
Because banks look at income after existing debt, not at income alone. Existing debts, open card limits and co-signing for somebody else all consume capacity first.
The bank valued it below the price. What now?
Three options: find the difference in cash, renegotiate the price, or apply to another bank that may value it differently. Ask about this before paying a large deposit.
Is it harder to borrow when self employed?
Harder if income never passes through an account, because what counts is what can be proved. The fix is running the account consistently for several months before applying, which is why preparing early matters.
Do LTV rules really change?
Yes, because the Bank of Thailand sets them and adjusts them with economic conditions. The most recent temporary relaxation runs to 30 June 2026, so ask which rule applies on the day you apply.
Does closing credit cards help?
Yes, because banks look at the credit you can reach rather than what you have used. But close them far enough ahead, since the information takes time to travel from the institution into the system.
In short
- There are four groups of reasons for refusal, and a blacklist is not one of them.
- The most common is debt to income, which you can calculate before applying.
- Income that counts is income that can be proved and passes through an account.
- The problem may be the property rather than you.
- Some banks do not lend in some areas, which is why another bank approves the same person.
- LTV rules change, and the latest temporary relaxation runs to 30 June 2026.
- Do not fire applications at several banks, and do not borrow informally for a deposit.
- The six month plan is: find the cause, clear small debts, close unused limits, run the account, then reapply.
- Ask a bank what is possible before applying, because that question costs nothing.