Daily = (1 + yearly)^(1/365) - 1 or Daily = (1 + monthly)^(1/30) - 1 

Thanx dear Laaradh for your cooperation.

Dear Prof. Iqbal

You can convert low frequency data into high using Eviews. Open up your workfile into Eviews, click on "new page" choose first option "specify by frequency/range", choose monthly/quarterly from drop down menus on right, then click ok. 

Now copy the variable from initial page and apply paste special in newly generated page. Select your desired frequency, choose linear, then click ok. I am sure it will work. If you face any problem float your query.

Also browse the givenn link: https://www.youtube.com/results?search_query=how+to+convert+annual+data+to+quarterly+data+

your welcome Yasir Hussain

Dear Researcher Mr. Yasir

You can easily find daily data for t-bill.. see for example https://www.treasury.gov/resource-center/data-chart-center/interest-rates/Pages/TextView.aspx?data=billrates

If you are unable to find for your focus country, you can convert using eviews... If the link I shared doesn't serve your purpose, lemme know.

if we use the above mentioned formula for converting monthly rate into daily it's coming in negative. Can we use still the formula?

Hi,

How do you convert annualized t.bills rates into monthly rates before using them for analysis?