Going through ECB data one can find interest rates on new and outstanding loans for various sectors of the economy, mainly non-financial sectors and households. Although investment is mainly driven by demand, one can use the interest rate on outstanding amounts (with original maturity of more than 1 year) as an indicator of the actual financial burden on economic players.
Here’s the interest rates on loans to non-financial corporations:
Most of the periphery actually faced lower interest rates than Germany (and the Euro area) during the boom years, especially Spain, making investment/housing projects even more viable and profitable. Greece and Germany followed a line almost 100bp higher. That changed around 2006 with the Euro area rate increasing (since the ECB increased its key interest rates) and spreads for most of the periphery countries starting to widen considerably, especially for Greece. At the end of 2009 rates for Germany were lower than the Euro area rate while periphery rates were a lot higher with the exception of Spain.
Since the start of the Euro crisis, German rates have again moved higher than Euro rates, while periphery rates are considerably lower. The two exceptions are Greece which faces a spread of almost 150bp and Portugal with a spread of 50bp.
As for interest rates on outstanding amounts of loans for home purchases:
the main conclusions are quite similar. Periphery rates were close or significantly below Euro area rates up until 2006 and reached positive spreads after 2007 probably contributing to the financial crisis. Since 2009 they are much lower than Euro area rates, especially in Portugal, Ireland and Spain helping the recovery, while Greek rates are lower than Euro area (in contrast with non-financial corporations rates).
Obviously, the reverse is true in terms of banks interest income. Given the fact that the periphery countries face a large capital flight (and corresponding Target2 liabilities which need to be financed by central bank lending) and higher funding costs on deposits/interbank lending, effective margins are significantly lower, hurting bank profits, especially since NPLs have increased.