This paper attempts to analyse "to shite iru" from the point of view of the exchange of information.
The "ru" form of the verb and the "te iru" form of the verb have been explained to have almost the same function when they state everyday habits. However, they are distinguished by the quality of information coming before them. The "te iru" form of the verb is a marked expression requiring more highly information than the "ru" form, which means "te iru" has the function to store information.
Therefore, in the sentence of "S wa P to itte iru", the "te iru" form is used to keep information gotten from S, then to give it to readers or listeners in the form of quotation from S's statement. The same function is applied to "～to setsumei shite iru" "～to nobete iru" "～to hanasite iru".
The most remarkable expression to store and indicate information is "to shite iru". In order to illustrate this, some sample sentences using "to shite iru" were inspected.
The results are as follows:
1) "to shite iru" needs to be preceded by some information which is considered by the speaker to be particularly worthwhile informing others.
2) The subject of "to shite iru" is some institution (I) or some group of people (G), so that other dynamic verbs can not follow it.
3) "I or G wa/dewa Q to shite iru" resembles "S dewa/ni yoruto Q souda", which means "I heard the news from someone". However, "to shite iru" implies "we (mass media) got information from some institution or some group to inform you (readers or listeners)".
Thus, "to shite iru" which has function to store and give information is used by the mass media especially in newspapers or broadcasting.