  We consider the nonleptonic and semileptonic decays of $D_s$-mesons into
$\phi$ and $f_0(980)$ mesons. QCD sum rules are used to calculate the form
factors associated with these decays, and the correspondig decay rates. On the
basis of data on $D_s^+\to\pi^+\pi^+\pi^-$, which goes dominantly via the
transition $D_s^+\to \pi^+f_0(980)$, we conclude that there is space for a
sizeable light quark component on $f_0(980)$.
