diff --git a/web/components/charts/contract/binary.tsx b/web/components/charts/contract/binary.tsx
index a3f04a29..564ef68c 100644
--- a/web/components/charts/contract/binary.tsx
+++ b/web/components/charts/contract/binary.tsx
@@ -25,19 +25,19 @@ const getBetPoints = (bets: Bet[]) => {
   return sortBy(bets, (b) => b.createdTime).map((b) => ({
     x: new Date(b.createdTime),
     y: b.probAfter,
-    datum: b,
+    obj: b,
   }))
 }
 
-const BinaryChartTooltip = (props: TooltipProps<HistoryPoint<Bet>>) => {
-  const { p, xScale } = props
-  const { x, y, datum } = p
+const BinaryChartTooltip = (props: TooltipProps<Date, HistoryPoint<Bet>>) => {
+  const { data, mouseX, xScale } = props
   const [start, end] = xScale.domain()
+  const d = xScale.invert(mouseX)
   return (
     <Row className="items-center gap-2">
-      {datum && <Avatar size="xs" avatarUrl={datum.userAvatarUrl} />}
-      <span className="font-semibold">{formatDateInRange(x, start, end)}</span>
-      <span className="text-greyscale-6">{formatPct(y)}</span>
+      {data.obj && <Avatar size="xs" avatarUrl={data.obj.userAvatarUrl} />}
+      <span className="font-semibold">{formatDateInRange(d, start, end)}</span>
+      <span className="text-greyscale-6">{formatPct(data.y)}</span>
     </Row>
   )
 }
diff --git a/web/components/charts/contract/choice.tsx b/web/components/charts/contract/choice.tsx
index 7c9ec07a..665a01cd 100644
--- a/web/components/charts/contract/choice.tsx
+++ b/web/components/charts/contract/choice.tsx
@@ -114,7 +114,7 @@ const getBetPoints = (answers: Answer[], bets: Bet[]) => {
     points.push({
       x: new Date(bet.createdTime),
       y: answers.map((a) => sharesByOutcome[a.id] ** 2 / sharesSquared),
-      datum: bet,
+      obj: bet,
     })
   }
   return points
@@ -181,12 +181,12 @@ export const ChoiceContractChart = (props: {
   const yScale = scaleLinear([0, 1], [height - MARGIN_Y, 0])
 
   const ChoiceTooltip = useMemo(
-    () => (props: TooltipProps<MultiPoint<Bet>>) => {
-      const { p, xScale } = props
-      const { x, y, datum } = p
+    () => (props: TooltipProps<Date, MultiPoint<Bet>>) => {
+      const { data, mouseX, xScale } = props
       const [start, end] = xScale.domain()
+      const d = xScale.invert(mouseX)
       const legendItems = sortBy(
-        y.map((p, i) => ({
+        data.y.map((p, i) => ({
           color: CATEGORY_COLORS[i],
           label: answers[i].text,
           value: formatPct(p),
@@ -197,9 +197,11 @@ export const ChoiceContractChart = (props: {
       return (
         <>
           <Row className="items-center gap-2">
-            {datum && <Avatar size="xxs" avatarUrl={datum.userAvatarUrl} />}
+            {data.obj && (
+              <Avatar size="xxs" avatarUrl={data.obj.userAvatarUrl} />
+            )}
             <span className="text-semibold text-base">
-              {formatDateInRange(x, start, end)}
+              {formatDateInRange(d, start, end)}
             </span>
           </Row>
           <Legend className="max-w-xs" items={legendItems} />
diff --git a/web/components/charts/contract/numeric.tsx b/web/components/charts/contract/numeric.tsx
index ac300361..f8051308 100644
--- a/web/components/charts/contract/numeric.tsx
+++ b/web/components/charts/contract/numeric.tsx
@@ -21,12 +21,15 @@ const getNumericChartData = (contract: NumericContract) => {
   }))
 }
 
-const NumericChartTooltip = (props: TooltipProps<DistributionPoint>) => {
-  const { x, y } = props.p
+const NumericChartTooltip = (
+  props: TooltipProps<number, DistributionPoint>
+) => {
+  const { data, mouseX, xScale } = props
+  const x = xScale.invert(mouseX)
   return (
     <>
       <span className="text-semibold">{formatLargeNumber(x)}</span>
-      <span className="text-greyscale-6">{formatPct(y, 2)}</span>
+      <span className="text-greyscale-6">{formatPct(data.y, 2)}</span>
     </>
   )
 }
diff --git a/web/components/charts/contract/pseudo-numeric.tsx b/web/components/charts/contract/pseudo-numeric.tsx
index adf2e493..04b1fafb 100644
--- a/web/components/charts/contract/pseudo-numeric.tsx
+++ b/web/components/charts/contract/pseudo-numeric.tsx
@@ -37,19 +37,21 @@ const getBetPoints = (bets: Bet[], scaleP: (p: number) => number) => {
   return sortBy(bets, (b) => b.createdTime).map((b) => ({
     x: new Date(b.createdTime),
     y: scaleP(b.probAfter),
-    datum: b,
+    obj: b,
   }))
 }
 
-const PseudoNumericChartTooltip = (props: TooltipProps<HistoryPoint<Bet>>) => {
-  const { p, xScale } = props
-  const { x, y, datum } = p
+const PseudoNumericChartTooltip = (
+  props: TooltipProps<Date, HistoryPoint<Bet>>
+) => {
+  const { data, mouseX, xScale } = props
   const [start, end] = xScale.domain()
+  const d = xScale.invert(mouseX)
   return (
     <Row className="items-center gap-2">
-      {datum && <Avatar size="xs" avatarUrl={datum.userAvatarUrl} />}
-      <span className="font-semibold">{formatDateInRange(x, start, end)}</span>
-      <span className="text-greyscale-6">{formatLargeNumber(y)}</span>
+      {data.obj && <Avatar size="xs" avatarUrl={data.obj.userAvatarUrl} />}
+      <span className="font-semibold">{formatDateInRange(d, start, end)}</span>
+      <span className="text-greyscale-6">{formatLargeNumber(data.y)}</span>
     </Row>
   )
 }
diff --git a/web/components/charts/generic-charts.tsx b/web/components/charts/generic-charts.tsx
index 5ae30ad4..152b264c 100644
--- a/web/components/charts/generic-charts.tsx
+++ b/web/components/charts/generic-charts.tsx
@@ -13,6 +13,7 @@ import {
 import { range } from 'lodash'
 
 import {
+  ContinuousScale,
   SVGChart,
   AreaPath,
   AreaWithTopStroke,
@@ -31,6 +32,19 @@ const getTickValues = (min: number, max: number, n: number) => {
   return [min, ...range(1, n - 1).map((i) => min + step * i), max]
 }
 
+const betAtPointSelector = <X, Y, P extends Point<X, Y>>(
+  data: P[],
+  xScale: ContinuousScale<X>
+) => {
+  const bisect = bisector((p: P) => p.x)
+  return (posX: number) => {
+    const x = xScale.invert(posX)
+    const item = data[bisect.left(data, x) - 1]
+    const result = item ? { ...item, x: posX } : undefined
+    return result
+  }
+}
+
 export const DistributionChart = <P extends DistributionPoint>(props: {
   data: P[]
   w: number
@@ -39,7 +53,7 @@ export const DistributionChart = <P extends DistributionPoint>(props: {
   xScale: ScaleContinuousNumeric<number, number>
   yScale: ScaleContinuousNumeric<number, number>
   onMouseOver?: (p: P | undefined) => void
-  Tooltip?: TooltipComponent<P>
+  Tooltip?: TooltipComponent<number, P>
 }) => {
   const { color, data, yScale, w, h, Tooltip } = props
 
@@ -50,7 +64,6 @@ export const DistributionChart = <P extends DistributionPoint>(props: {
   const px = useCallback((p: P) => xScale(p.x), [xScale])
   const py0 = yScale(yScale.domain()[0])
   const py1 = useCallback((p: P) => yScale(p.y), [yScale])
-  const xBisector = bisector((p: P) => p.x)
 
   const { xAxis, yAxis } = useMemo(() => {
     const xAxis = axisBottom<number>(xScale).ticks(w / 100)
@@ -58,6 +71,8 @@ export const DistributionChart = <P extends DistributionPoint>(props: {
     return { xAxis, yAxis }
   }, [w, xScale, yScale])
 
+  const onMouseOver = useEvent(betAtPointSelector(data, xScale))
+
   const onSelect = useEvent((ev: D3BrushEvent<P>) => {
     if (ev.selection) {
       const [mouseX0, mouseX1] = ev.selection as [number, number]
@@ -69,14 +84,6 @@ export const DistributionChart = <P extends DistributionPoint>(props: {
     }
   })
 
-  const onMouseOver = useEvent((mouseX: number) => {
-    const queryX = xScale.invert(mouseX)
-    const item = data[xBisector.left(data, queryX) - 1]
-    const result = item ? { ...item, x: queryX } : undefined
-    props.onMouseOver?.(result)
-    return result
-  })
-
   return (
     <SVGChart
       w={w}
@@ -107,7 +114,7 @@ export const MultiValueHistoryChart = <P extends MultiPoint>(props: {
   xScale: ScaleTime<number, number>
   yScale: ScaleContinuousNumeric<number, number>
   onMouseOver?: (p: P | undefined) => void
-  Tooltip?: TooltipComponent<P>
+  Tooltip?: TooltipComponent<Date, P>
   pct?: boolean
 }) => {
   const { colors, data, yScale, w, h, Tooltip, pct } = props
@@ -119,7 +126,6 @@ export const MultiValueHistoryChart = <P extends MultiPoint>(props: {
   const px = useCallback((p: SP) => xScale(p.data.x), [xScale])
   const py0 = useCallback((p: SP) => yScale(p[0]), [yScale])
   const py1 = useCallback((p: SP) => yScale(p[1]), [yScale])
-  const xBisector = bisector((p: P) => p.x)
 
   const { xAxis, yAxis } = useMemo(() => {
     const [min, max] = yScale.domain()
@@ -141,6 +147,8 @@ export const MultiValueHistoryChart = <P extends MultiPoint>(props: {
     return d3Stack(data)
   }, [data])
 
+  const onMouseOver = useEvent(betAtPointSelector(data, xScale))
+
   const onSelect = useEvent((ev: D3BrushEvent<P>) => {
     if (ev.selection) {
       const [mouseX0, mouseX1] = ev.selection as [number, number]
@@ -152,14 +160,6 @@ export const MultiValueHistoryChart = <P extends MultiPoint>(props: {
     }
   })
 
-  const onMouseOver = useEvent((mouseX: number) => {
-    const queryX = xScale.invert(mouseX)
-    const item = data[xBisector.left(data, queryX) - 1]
-    const result = item ? { ...item, x: queryX } : undefined
-    props.onMouseOver?.(result)
-    return result
-  })
-
   return (
     <SVGChart
       w={w}
@@ -193,7 +193,7 @@ export const SingleValueHistoryChart = <P extends HistoryPoint>(props: {
   xScale: ScaleTime<number, number>
   yScale: ScaleContinuousNumeric<number, number>
   onMouseOver?: (p: P | undefined) => void
-  Tooltip?: TooltipComponent<P>
+  Tooltip?: TooltipComponent<Date, P>
   pct?: boolean
 }) => {
   const { color, data, yScale, w, h, Tooltip, pct } = props
@@ -204,7 +204,6 @@ export const SingleValueHistoryChart = <P extends HistoryPoint>(props: {
   const px = useCallback((p: P) => xScale(p.x), [xScale])
   const py0 = yScale(yScale.domain()[0])
   const py1 = useCallback((p: P) => yScale(p.y), [yScale])
-  const xBisector = bisector((p: P) => p.x)
 
   const { xAxis, yAxis } = useMemo(() => {
     const [min, max] = yScale.domain()
@@ -218,6 +217,8 @@ export const SingleValueHistoryChart = <P extends HistoryPoint>(props: {
     return { xAxis, yAxis }
   }, [w, h, pct, xScale, yScale])
 
+  const onMouseOver = useEvent(betAtPointSelector(data, xScale))
+
   const onSelect = useEvent((ev: D3BrushEvent<P>) => {
     if (ev.selection) {
       const [mouseX0, mouseX1] = ev.selection as [number, number]
@@ -229,14 +230,6 @@ export const SingleValueHistoryChart = <P extends HistoryPoint>(props: {
     }
   })
 
-  const onMouseOver = useEvent((mouseX: number) => {
-    const queryX = xScale.invert(mouseX)
-    const item = data[xBisector.left(data, queryX) - 1]
-    const result = item ? { ...item, x: queryX } : undefined
-    props.onMouseOver?.(result)
-    return result
-  })
-
   return (
     <SVGChart
       w={w}
diff --git a/web/components/charts/helpers.tsx b/web/components/charts/helpers.tsx
index ba9865b2..ea221c80 100644
--- a/web/components/charts/helpers.tsx
+++ b/web/components/charts/helpers.tsx
@@ -17,7 +17,12 @@ import clsx from 'clsx'
 
 import { Contract } from 'common/contract'
 
-export type Point<X, Y, T = unknown> = { x: X; y: Y; datum?: T }
+export type Point<X, Y, T = unknown> = { x: X; y: Y; obj?: T }
+
+export interface ContinuousScale<T> extends AxisScale<T> {
+  invert(n: number): T
+}
+
 export type XScale<P> = P extends Point<infer X, infer _> ? AxisScale<X> : never
 export type YScale<P> = P extends Point<infer _, infer Y> ? AxisScale<Y> : never
 
@@ -118,18 +123,18 @@ export const AreaWithTopStroke = <P,>(props: {
   )
 }
 
-export const SVGChart = <X, Y, P extends Point<X, Y>>(props: {
+export const SVGChart = <X, TT>(props: {
   children: ReactNode
   w: number
   h: number
   xAxis: Axis<X>
   yAxis: Axis<number>
   onSelect?: (ev: D3BrushEvent<any>) => void
-  onMouseOver?: (mouseX: number, mouseY: number) => P | undefined
-  Tooltip?: TooltipComponent<P>
+  onMouseOver?: (mouseX: number, mouseY: number) => TT | undefined
+  Tooltip?: TooltipComponent<X, TT>
 }) => {
   const { children, w, h, xAxis, yAxis, onMouseOver, onSelect, Tooltip } = props
-  const [mouseState, setMouseState] = useState<{ pos: TooltipPosition; p: P }>()
+  const [mouse, setMouse] = useState<{ x: number; y: number; data: TT }>()
   const overlayRef = useRef<SVGGElement>(null)
   const innerW = w - MARGIN_X
   const innerH = h - MARGIN_Y
@@ -148,7 +153,7 @@ export const SVGChart = <X, Y, P extends Point<X, Y>>(props: {
         if (!justSelected.current) {
           justSelected.current = true
           onSelect(ev)
-          setMouseState(undefined)
+          setMouse(undefined)
           if (overlayRef.current) {
             select(overlayRef.current).call(brush.clear)
           }
@@ -168,26 +173,32 @@ export const SVGChart = <X, Y, P extends Point<X, Y>>(props: {
 
   const onPointerMove = (ev: React.PointerEvent) => {
     if (ev.pointerType === 'mouse' && onMouseOver) {
-      const [mouseX, mouseY] = pointer(ev)
-      const p = onMouseOver(mouseX, mouseY)
-      if (p != null) {
-        const pos = getTooltipPosition(mouseX, mouseY, innerW, innerH)
-        setMouseState({ pos, p })
+      const [x, y] = pointer(ev)
+      const data = onMouseOver(x, y)
+      if (data !== undefined) {
+        setMouse({ x, y, data })
       } else {
-        setMouseState(undefined)
+        setMouse(undefined)
       }
     }
   }
 
   const onPointerLeave = () => {
-    setMouseState(undefined)
+    setMouse(undefined)
   }
 
   return (
     <div className="relative">
-      {mouseState && Tooltip && (
-        <TooltipContainer pos={mouseState.pos}>
-          <Tooltip xScale={xAxis.scale()} p={mouseState.p} />
+      {mouse && Tooltip && (
+        <TooltipContainer
+          pos={getTooltipPosition(mouse.x, mouse.y, innerW, innerH)}
+        >
+          <Tooltip
+            xScale={xAxis.scale()}
+            mouseX={mouse.x}
+            mouseY={mouse.y}
+            data={mouse.data}
+          />
         </TooltipContainer>
       )}
       <svg width={w} height={h} viewBox={`0 0 ${w} ${h}`}>
@@ -243,8 +254,13 @@ export const getTooltipPosition = (
   return result
 }
 
-export type TooltipProps<P> = { p: P; xScale: XScale<P> }
-export type TooltipComponent<P> = React.ComponentType<TooltipProps<P>>
+export type TooltipProps<X, T> = {
+  mouseX: number
+  mouseY: number
+  xScale: ContinuousScale<X>
+  data: T
+}
+export type TooltipComponent<X, T> = React.ComponentType<TooltipProps<X, T>>
 export const TooltipContainer = (props: {
   pos: TooltipPosition
   className?: string