Financing Single-family house 520TE current market situation / year-end business banks?

On Thursday is the ECB key interest rate decision where at least 0.5 or even 0.75 will be increased. So if you finance, then best by Wednesday.

Sorry, but you are talking nonsense with that. Besides the fact that there are three important key interest rates of the ECB, the key interest rate always mentioned in the press initially has no impact on the current interest rate development in the market (long-term loans). And now I will be really mean and say: wait for the key interest rate increase and finance afterwards. After the last key interest rate increase, the average rate for 10-year fixed interest rates has fallen by 0.60% until today (in 1.5 months). So much for the ECB interest rate hike and construction financing rates ;)

We have now had calculations done by 2 different independent financial advisors, and a conversation with the Commerzbank (house bank) is still pending. Is this in any way harmful to our creditworthiness or anything similar? Do you think a local bank can compete with an ING (currently the "cheapest")?

I have completed three financings this year. One for a new property, 2x Forward (for 2023 and for 2025). Twice Commerzbank significantly undercut ING, once ING was successful.

Is that harmful in any way to our credit rating or something like that?

In general, there are two types of inquiries. One is a conditions inquiry (what credit brokers usually do to compare offers), the other is the actual credit inquiry (=> you go through the proper process with a credit contract being set up, etc.). The former (conditions inquiry) is, as far as I know, not harmful to Schufa, the latter (credit inquiry) is reported to Schufa, is somehow visible to other banks for a few days (10?), basically so you don't take out multiple loans in parallel and thus deceive the banks or something similar, and is only completely deleted by Schufa after about a year, I think. How harmful or not that is, I can't say (if a credit inquiry completely fails, I would probably play open cards in subsequent inquiries anyway, since they see it anyway). This doesn’t have to be a knockout criterion if there is a credit inquiry, but generally most people try to make only one proper credit inquiry when they are seriously interested in taking out a loan with that exact bank.

Do you think a local bank can compete with an ING (currently the "cheapest")?

That can vary a lot. Others have already written here that they had positive experiences with local banks; in our case, they were mostly more than a percent above what brokers offered. But we never pursued that in depth. It was also a pretty exciting phase for us, when interest rates were adjusted partly daily and sometimes jumped by 0.5-0.6% from one week to the next (apparently local banks around here preferred to build in a bigger buffer and adjust less frequently). I think it’s a bit more stable now (though still volatile), but who knows.

I have completed three financings this year. Once for a new property, twice forward (for 2023 and for 2025). Twice Commerzbank clearly underbid ING, once ING was successful.

So the brokers can also access Commerzbank's offers. Shouldn't the conditions be roughly the same... Or do local banks have more room to maneuver?! I find the topic of land quite interesting, but for the customer really annoying because there are such big differences. Especially with the amount we want to finance

With us, the lady at Commerzbank had more leeway and was thus able to better tailor the loan to our needs. As a result, a better product came out. For example, she could conclude two loans with different conditions (e.g., different length of commitment fees, special repayments), was more flexible with the repayment (the broker could only offer the Commerzbank loan with 2% repayment, which made no sense for the rented property), could "play" a bit with the valuation, etc.

In total, it was worth it for us to try both routes, and for fun, I also took the appointment at the local Volksbank (the appointment was already scheduled anyway), who were annoyingly complicated and snobbish, and I left the appointment laughing after about 10 minutes when they told me the possible conditions.