Estimation of many equation?

[mfan]

hello,
I've created a series of 25 portfolios excess return and need to regress them against the market excess return, the classical capm model
ri-rf = c + b(rm-rf) + e
the question is: how can i perform a simultaneously regression on the 25 portfolios? Is there any way to do so or do I've regress them one by one?
and once i've done it how do i export the results on excel without having the format data problem?
thanks

[Martin B]

Disclaimer right at the beginning: my advice must not necessariliy be true!

you could estimate a system of seemingly unrelated regression equation. Doing so, you take into account that the error terms of your 25 equations have a relationship.

Objects, New Objects, System, estimate with Seemingly Unrelated. You have to type in 25 regressions in the spec file.

Kind regards