  The EUV provides most of the ionization that creates the high equivalent
width (EW) broad and narrow emission lines (BELs, NELs) of quasars. Spectra of
Hypermassive Schwarzschild black holes (HMBHs, $M_{BH} \geq 10^{10} M_{\odot}$)
with $\alpha$-discs, decline rapidly in the EUV suggesting much lower EWs.
Model spectra for black holes of mass $10^{6}-10^{12} M_{\odot}$ and accretion
rates $0.03 \leq L_{bol}/L_{edd} \leq 1.0$ were input to the CLOUDY
photoionization code. BELs become $\sim$100 times weaker in EW from $M_{BH}
\sim 10^8 M_{\odot}$ to $M_{BH} \sim 10^{10} M_{\odot}$. The high ionization
BELs (O VI 1034 $\overset{\circ}{\mathrm {A}}$, C IV 1549
$\overset{\circ}{\mathrm {A}}$, He II 1640 $\overset{\circ}{\mathrm {A}}$)
decline in EW from ($M_{BH} \geq 10^6 M_{\odot}$, reproducing the Baldwin
effect, but regain EW for $M_{BH} \geq 10^{10} M_{\odot}$). The low ionization
lines (MgII 2798 $\overset{\circ}{\mathrm {A}}$, H$\beta$ 4861
$\overset{\circ}{\mathrm {A}}$ and H$\alpha$ 6563 $\overset{\circ}{\mathrm
{A}}$) remain weak. Lines for maximally spinning HMBHs behave similarly. Line
ratio diagrams for the BELs show that high OVI/H$\beta$ and low CIV/H$\alpha$
may pick out HMBH, although OVI is often hard to observe. In NEL BPT diagrams
HMBHs lie among star-forming regions, except for highly spinning, high
accretion rate HMBHs. In summary, the BELs expected from HMBHs would be hard to
detect using the current optical facilities. From 100 to $10^{12} M_{\odot}$,
the emission lines used to detect AGN only have high EW in the $10^6 - 10^9
M_{\odot}$ window, where most AGN are found. This selection effect may be
distorting reported distributions of $M_{BH}$.
