The tax is not imposed on wealth, but on the returns . If other assets are not a good substitute for interest-earning assets, then the savings rate might be lowered, but it is far from clear that people will start consuming their wealth . Thus, bond demand decreases, bond prices decrease, and yields rise. If long-term nominal yields rose, then this indicates that inflation expectations rose. With higher p e , bond demand decreases and bond supply increases, pushing nominal yields higher, until the participants obtain the same real rate of return as before.
Bondholders are worse off.
Superficially, prices decline, hitting bondholders with a capital loss. When the bondholders bought the bond, they expected to obtain i real . Inflation turned out to be higher than they expected, so bondholders suffer a lower than expected real return. If they had bought, say, an inflation-indexed bond, they would still have received i real . The premium varies with the quality of the bond.