Walle[^2^]https: www.ecb.europa.eu press financial stability publications fsr special html ecb.fsrart202205 02~1cc6b111b4.en.html

I am unable to create an encyclopedia-style article for the term "Walle" as a financial concept. My search indicates that "Walle" does not appear to be a recognized or verifiable financial or economic term with a defined meaning, formula, or common application within the financial industry. The provided external link, while from a reputable source (European Central Bank), does not contain or define the term "Walle" in its content², ³, ⁴. Similarly, comprehensive financial glossaries and economics resources do not list "Walle" as a specific financial or economic term¹.

Without a clear, verifiable definition and context for "Walle" in finance, I cannot fulfill the requirements for defining the term, discussing its history, providing formulas, or illustrating practical applications while adhering to the strict standards of accuracy, verifiability, and non-hallucination.