When dealing with unconfirmed information, you rarely have the full story. In Italian, you can restrict the scope of your claims using a limitative clause, typically introduced by per quanto (as far as).
The Indicative for Fixed Expressions
The most common way to say "as far as I know" is the fixed expression per quanto ne so. It uses the indicative mood and includes the pronoun ne (about it).
| As far as I know, the alleged thief is innocent. | Per quanto ne so, il presunto ladro è innocente. |
The Subjunctive for Subjective Limits
When you want to emphasize that your limitation is subjective—relying on your own memory or personal knowledge—use the subjunctive mood. Because singular subjunctive conjugations are identical, it is common to include the subject pronoun (io) for clarity.
| As far as I know, the news is unofficial, but I do not know the journalist. | Per quanto io sappia, la notizia è ufficiosa, ma non conosco il giornalista. |
| As far as I remember, the tip-off comes from the colleague of whom we spoke. | Per quanto io ricordi, la soffiata arriva dal collega di cui abbiamo parlato. |
You can also apply this subjective nuance to our first phrase: per quanto ne sappia is completely interchangeable with per quanto ne so.
| As far as I know, this confidential document is vaguely true. | Per quanto ne sappia, questo documento confidenziale è vagamente vero. |
The Indicative for Concrete Actions
If the limit of your knowledge is based on a concrete, factual action you took—such as what you have read—use the indicative mood.
| As far as I have read, the denial of the alleged scandal is false. | Per quanto ho letto, la smentita del presunto scandalo è falsa. |
