how to describe this pattern in Leonardo Finmeccanica's share price (observed here)? It is a fairly liquid stock, but the price seems to alternate between ca. 8 and ca 13!!
Does anyone know what could explain this observation?
Seems like the least interesting pattern of all - data errors at the Yahoo's side. Just checked with Bloomberg - nothing similar is present.
If not a data error, this could be bid-ask bounce (dismissed with here since you mention it's a liquid stock).